Check if a number is prime, see its factors, and list all primes up to any number.
Enter any whole number to instantly check whether it's prime. If it isn't, all its factors are shown. You can also list every prime number up to a chosen limit.
A prime number is a whole number greater than 1 that has exactly two factors: 1 and itself. The first few primes are 2, 3, 5, 7, 11, 13...