What is prime factorization?

Writing an integer greater than 1 as a product of primes, e.g. 360 = 2×2×2×3×3×5 = 2³×3²×5. That factorization is unique.

No. A prime has exactly two positive divisors, 1 and itself; 1 has only one, so it is neither prime nor composite.

How large a number can it factor?

Up to 10^13. Wheel trial division makes everyday numbers instant.

How many primes can the list show?

Any range covering at most 20000 consecutive integers, and the whole list can be copied at once.

🔢

🔢Prime Factorization Calculator - Factor, Prime Check and Prime List

Enter an integer and get its prime factorization (for example 360 = 2³ × 3² × 5), every divisor and the sum of the divisors. You can also test whether a number is prime, find the previous and next prime, or list all primes in a range.

Free · No sign-up · Runs in your browserLast updated: 2026-10-26

Loading tool...

How to use Prime Factorization

1Choose factorization, prime check or prime list
2Enter the integer, or the start and end of the range
3Read the result and copy it in one click

FAQ

What is prime factorization?: Writing an integer greater than 1 as a product of primes, e.g. 360 = 2×2×2×3×3×5 = 2³×3²×5. That factorization is unique.
Is 1 a prime number?: No. A prime has exactly two positive divisors, 1 and itself; 1 has only one, so it is neither prime nor composite.
How large a number can it factor?: Up to 10^13. Wheel trial division makes everyday numbers instant.
How many primes can the list show?: Any range covering at most 20000 consecutive integers, and the whole list can be copied at once.