Prime Number Calculator
Check if a number is prime, find its prime factors, or get a list of prime numbers up to a limit.
What Is a Prime Number?
Definition
A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself.
First 20 Primes
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71
Quick Rules
- 2 is the only even prime number.
- 1 is not a prime number.
- All primes > 2 are odd.
- All primes > 3 end in 1, 3, 7, or 9.
