Break any whole number into its prime factors, and check whether it’s prime.
What this calculator does
Enter a whole number and this calculator finds its prime factorization — the unique set of prime numbers that multiply to give it — and tells you if the number itself is prime.
Prime factors underpin GCF, LCM and fraction simplification.
Worked example
Worked through, a whole number of 360 produces a prime factors of 2 × 2 × 2 × 3 × 3 × 5. Underneath, Factorization comes out at 2^3 × 3^2 × 5 and Number of factors at 6. Change any field and every figure updates as you type.
How to use it
- Enter a whole number of 2 or more.
- Read the prime factorization.
- See whether the number is prime.
How the number is calculated
divide by the smallest prime repeatedly,
moving up until only 1 remains
Frequently asked questions
What is prime factorization?
Writing a number as a product of prime numbers, like 360 = 2³ × 3² × 5. Every whole number has exactly one.
What makes a number prime?
It has exactly two divisors: 1 and itself. If the factorization has a single factor, the number is prime.
What is it used for?
Simplifying fractions, finding GCF and LCM, and cryptography, among others.