Factor Calculator

Video Guide: Factor Calculator

Video guide with full transcript

About Factor Calculator

Welcome to the Factor Calculator with Steps, a powerful free online tool that finds all factors of any positive integer with a clear, step-by-step factorization process. This calculator provides comprehensive factor analysis including factor pairs, prime factorization with an interactive factor tree diagram, and detailed number properties. Whether you are a student learning about divisibility, a teacher preparing lessons, or anyone working with number theory, this tool delivers fast and accurate results with detailed steps.

What Are Factors?

Factors (also called divisors) of a number are all the positive integers that divide evenly into that number with no remainder. Every positive integer has at least two factors: 1 and itself. For example, the factors of 12 are 1, 2, 3, 4, 6, and 12 because each of these numbers divides 12 exactly without leaving a remainder.

Understanding Factor Pairs

Factor pairs are two numbers that multiply together to give the original number. Each factor has a corresponding pair factor. For 24, the factor pairs are:

• 1 × 24 = 24
• 2 × 12 = 24
• 3 × 8 = 24
• 4 × 6 = 24

How to Find Factors of a Number

To find all factors of a number systematically:

1. Enter the number: Type a positive integer into the input field. You can enter numbers up to 999,999,999,999 (999 billion).
2. Calculate factors: Click the Calculate Factors button or press Enter to find all factors of your number.
3. View all factors: See the complete list of all positive divisors sorted from smallest to largest.
4. Explore factor pairs: View factor pairs displayed as multiplication equations showing which two numbers multiply to give your original number.
5. Analyze prime factorization: See the prime factorization in both expanded form (showing all prime factors) and exponential notation, with an interactive factor tree diagram.

Step-by-Step Example: Finding Factors of 72

Here is a complete step-by-step walkthrough of how to find all factors of 72:

1. Step 1 — Start with 1: 72 ÷ 1 = 72, so 1 and 72 are factors.
2. Step 2 — Try 2: 72 ÷ 2 = 36, so 2 and 36 are factors.
3. Step 3 — Try 3: 72 ÷ 3 = 24, so 3 and 24 are factors.
4. Step 4 — Try 4: 72 ÷ 4 = 18, so 4 and 18 are factors.
5. Step 5 — Try 5: 72 ÷ 5 = 14.4 (not a whole number) — skip.
6. Step 6 — Try 6: 72 ÷ 6 = 12, so 6 and 12 are factors.
7. Step 7 — Try 7: 72 ÷ 7 = 10.28... (not a whole number) — skip.
8. Step 8 — Try 8: 72 ÷ 8 = 9, so 8 and 9 are factors.
9. Step 9 — Stop: The next number to try is 9, and 9 × 9 = 81 > 72, so we stop here.

Result: The factors of 72 are 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, 72 (12 factors total).

This step-by-step trial division method works for any number. You only need to test divisors up to the square root of the number, because each divisor you find automatically gives you a paired factor above the square root.

What is Prime Factorization?

Prime factorization is the process of expressing a number as a product of prime numbers. Every composite number can be written as a unique product of primes (this is the Fundamental Theorem of Arithmetic). For example:

• 60 = 2 × 2 × 3 × 5 = 2² × 3 × 5
• 84 = 2 × 2 × 3 × 7 = 2² × 3 × 7
• 100 = 2 × 2 × 5 × 5 = 2² × 5²

Factor Tree: What It Is and How to Make One

A factor tree is a diagram that breaks a number down into its prime factors. You write the number at the top, split it into two factors that multiply to give it, and keep splitting every branch that is not prime until each branch ends in a prime number. Multiplied together, the primes at the ends of the branches are the number's prime factorization — which is why a factor tree is also called a prime factor tree.

How to Make a Factor Tree

1. Write the number at the top.
2. Split it into a factor pair. Choose any two numbers other than 1 that multiply to give it. For an even number, 2 is always an easy first branch.
3. Circle the primes. A prime branch is finished and becomes a leaf of the tree.
4. Keep splitting the other branches the same way until every branch ends in a circled prime.
5. Write the leaves as a product, smallest first, using exponents for repeated primes. Multiply them back out to check that you get the original number.

Example: Factor Tree of 24

The tree on the left starts with 24 = 2 × 12, then 12 = 2 × 6, then 6 = 2 × 3. The tree on the right starts with 24 = 4 × 6, then splits 4 = 2 × 2 and 6 = 2 × 3. Both end in the same four primes: 24 = 2 × 2 × 2 × 3 = 2³ × 3. Primes are shown in amber and composite numbers in purple, the same colors the calculator uses.

Does It Matter Which Factors You Start With?

No. A number can have several differently shaped factor trees, but every one of them ends in the same primes, because each whole number greater than 1 has exactly one prime factorization (the Fundamental Theorem of Arithmetic). Splitting off the smallest prime each time — 2, then 3, then 5, and so on — gives the most predictable tree, and that is the method this calculator uses: enter any number above and the Factor Tree panel draws its tree for you.

Factor Trees of Common Numbers

Each row splits off the smallest prime first, the same way the calculator does.

Key Features of This Calculator

• Complete Factor List: Find all positive divisors of any number up to 999 billion
• Factor Pairs Visualization: See all pairs of numbers that multiply to give your number
• Interactive Factor Tree: Visual SVG diagram showing prime factorization process
• Dual Prime Notation: Both expanded (2 × 2 × 3) and exponential (2² × 3) forms
• Number Analysis: Automatically detects prime numbers, perfect squares, and perfect cubes
• Statistics: Total factor count, sum of factors, smallest and largest prime factors
• One-Click Copy: Copy results to clipboard instantly

Understanding Number Properties

Prime Numbers vs Composite Numbers

A prime number is a positive integer greater than 1 that has exactly two factors: 1 and itself. Examples include 2, 3, 5, 7, 11, 13, 17, and so on. A composite number has more than two factors. The number 1 is special - it is neither prime nor composite.

Perfect Squares

A perfect square is a number that can be expressed as the product of an integer with itself. For example, 36 is a perfect square because 6 × 6 = 36. Perfect squares always have an odd number of factors because the square root appears only once in the factor list.

Perfect Cubes

A perfect cube is a number that can be expressed as the product of an integer multiplied by itself twice. For example, 27 is a perfect cube because 3 × 3 × 3 = 27.

Applications of Factors

Mathematics Education

Understanding factors is essential for learning multiplication, division, fractions, and algebra. Students use factors to simplify fractions, find greatest common divisors (GCD), and factor polynomials.

Finding GCD and LCM

The factors and prime factorization of numbers are used to find the Greatest Common Divisor (GCD) and Least Common Multiple (LCM). These calculations are fundamental in fraction arithmetic and solving equations.

Cryptography

Prime factorization is the foundation of RSA encryption, one of the most widely used cryptographic systems. The security relies on the difficulty of factoring very large numbers into their prime components.

Problem Solving

Factors help solve problems involving equal distribution, scheduling, arranging items in rectangular arrays, and many other practical applications.

Divisibility Rules Quick Reference

Use these rules to quickly check if a number is divisible by common factors:

• Divisible by 2: The number ends in 0, 2, 4, 6, or 8 (even numbers)
• Divisible by 3: The sum of digits is divisible by 3
• Divisible by 4: The last two digits form a number divisible by 4
• Divisible by 5: The number ends in 0 or 5
• Divisible by 6: The number is divisible by both 2 and 3
• Divisible by 9: The sum of digits is divisible by 9
• Divisible by 10: The number ends in 0

Frequently Asked Questions

What are the factors of a number?

Factors of a number are all the positive integers that divide evenly into that number with no remainder. For example, the factors of 12 are 1, 2, 3, 4, 6, and 12 because each of these numbers divides 12 exactly. Every number has at least two factors: 1 and itself.

How do I find all factors of a number?

To find all factors, start by dividing the number by 1, then 2, then 3, and so on up to the square root of the number. When you find a divisor, both the divisor and the quotient are factors. For example, for 36: 1 divides 36 giving 36, 2 divides 36 giving 18, 3 divides 36 giving 12, 4 divides 36 giving 9, and 6 divides 36 giving 6. So the factors are 1, 2, 3, 4, 6, 9, 12, 18, 36.

What is the difference between factors and prime factors?

Factors are all numbers that divide evenly into a given number, while prime factors are specifically the prime numbers that multiply together to give the original number. For example, 24 has factors 1, 2, 3, 4, 6, 8, 12, 24, but its prime factors are only 2 and 3 (since 24 = 2 × 2 × 2 × 3 = 2³ × 3).

What is a factor tree?

A factor tree is a diagram used to find the prime factorization of a number. You start with the original number and repeatedly divide it by its smallest prime factor, branching downward until all branches end in prime numbers. For example, 60 splits into 2 and 30, then 30 splits into 2 and 15, then 15 splits into 3 and 5. The prime factorization is 2 × 2 × 3 × 5 = 2² × 3 × 5.

How do you make a factor tree?

Write the number at the top and split it into any two factors that multiply to give it, such as 2 and 12 for 24. Circle any factor that is prime. Keep splitting each factor that is not prime into two smaller factors until every branch ends in a prime. The circled primes multiplied together are the prime factorization: for 24 that is 2 × 2 × 2 × 3 = 2³ × 3.

Can a number have more than one factor tree?

Yes. 24 can start as 2 × 12, 3 × 8 or 4 × 6, and each start gives a differently shaped tree. All of them end in the same primes, 2, 2, 2 and 3, because every whole number greater than 1 has exactly one prime factorization.

What are factor pairs?

Factor pairs are two numbers that multiply together to give the original number. Each factor of a number has a corresponding pair factor. For example, the factor pairs of 24 are (1, 24), (2, 12), (3, 8), and (4, 6). Factor pairs are useful for understanding multiplication relationships and for factoring in algebra.

What is the largest number this calculator supports?

This calculator can find factors of any positive integer up to 999,999,999,999 (999 billion). For most practical purposes, this range covers any factoring needs you might have.

Related Tools

Explore our other math calculators:

• Common Factor Calculator - Find common factors of two or more numbers
• GCF Calculator - Calculate the greatest common factor
• LCM Calculator - Find the least common multiple
• Prime Factor Calculator - Focus specifically on prime factorization

Basic Math Operations:

• Absolute Value Calculator New
• Amicable Number Checker New
• Carry and Borrow Visualizer New
• Ceiling and Floor Function Calculator New
• Common Factor Calculator
• Cross Multiplication Calculator New
• Cube and Cube Root Calculator
• Cube Root Calculator
• Digital Root Calculator New
• Divide Into Two Parts
• Divisibility Test Calculator
• Egyptian Multiplication Calculator New
• Estimation Calculator Popular
• Even or Odd Number Checker New
• Factor Calculator Popular
• Fibonacci Number Checker New
• Find Minimum and Maximum
• First n Digits of e Popular
• First n Digits of Pi Popular
• Goldbach Conjecture Verifier New
• Greatest Common Factor Calculator
• Is it a Prime Number?
• Least Common Multiple Calculator
• Long Addition and Subtraction Calculator New
• Long Division Calculator New
• Long Multiplication Calculator New
• Möbius Function Calculator New
• Mental Math Trainer New
• Mersenne Prime Checker New
• Modulo Calculator Popular
• Multiplication Calculator Popular
• Multiplication Table Generator New
• n-th Root Calculator
• Number Bonds Generator New
• Number of Digits Calculator Popular
• Number Pattern Finder New
• Order of Operations Calculator (PEMDAS) Popular
• Perfect Number Checker New
• Place Value Chart Generator New
• Prime Factor Calculator
• Prime Factorization Calculator
• Quotient and Remainder Calculator Popular
• Random Math Problem Generator Popular
• Ratio Calculator New
• Roman Numeral Math Solver New
• Russian Peasant Multiplication New
• Skip Counting Generator New
• Soroban Abacus Simulator New
• Sort Numbers Popular
• Square Root (√) Calculator Popular
• Sum Calculator Popular
• Times Tables Quiz New
• Unit Rate Calculator New
• Vedic Math Tricks Calculator New