Prime Number Checker
Check if a number is prime and see its factors.
97 is prime
It has exactly two divisors: 1 and itself.
Free online prime number checker. Enter any whole number to find out if it is prime, and if it isn't, see its full prime factorization. Fast trial-division runs in your browser.
How to use the Prime Number Checker
- 01Type a whole number.
- 02See instantly whether it is prime.
- 03If it isn't, the prime factorization and factors are shown.
Frequently asked questions
What is a prime number?
A prime number is a whole number greater than 1 whose only divisors are 1 and itself. Examples are 2, 3, 5, 7 and 11.
What does the factorization show?
For non-prime numbers the tool breaks the number into a product of primes, such as 60 = 2² × 3 × 5, and lists the distinct prime factors.