Prime Number Checker

Check if a number is prime, find prime factorization, and list primes in a range

Check a Number

Find Primes in a Range

to

Notable Primes

2
Smallest prime
3
Only prime divisible by 3
5
Only prime ending in 5
11
Smallest palindrome prime
101
Palindrome prime
1,000,003
10⁶ + 3, largest prime < 10⁶+4

How to use:

  • • Enter any positive integer and click Check to see if it is prime
  • • Non-prime numbers show their full prime factorization
  • • Use the range finder to list all primes between two numbers
  • • Click Copy to copy the prime list to your clipboard

Prime Numbers FAQ