Prime Number Calculator

Check if any number is prime, find its prime factorization, and list prime numbers up to a value.

Enter a positive integer

What is a Prime Number?

A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself.

Prime: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29…
Not prime (composite): 4, 6, 8, 9, 10, 12…

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71

Last updated: 2026-08-08