Waiting for you to type a number!

Auto Calculate (works for numbers <= 5000)

Type in whatever number you want and then choose which operation you want the prime factorization calculator to perform.

The prime factorization calculator can:

• Calculate the prime factorization of the number you type (Numbers above 10 million may or may not time out. Calculating the prime factorization of large numbers is not easy, but the calculator can handle pretty darn big ones!)
• Determine whether or not a number is prime
• Create sieve of Erasthones for the number
• Create a list of all positive prime numbers smaller than the number of your choice
• As an example, if you want the calculator to determine how many primes are before the number 11, just type in the number 11, then select "List of Primes before""" and the it will promptly output '5' (The 5 positive primes smaller than the number 11 are 2, 3, 5,7 and 11).
• Calculate how many prime numbers are smaller than the number of your choice
• As an example, if you want the prime factorization calculator to determine how many primes are before the number 11, just type in the number 11, then select and the calculator will promptly create a list of the numbers 2, 3, 5 and 7.