It looks like you're using Internet Explorer 11 or older. This website works best with modern browsers such as the latest versions of Chrome, Firefox, Safari, and Edge. If you continue with this browser, you may see unexpected results.

Topic: Prime Factorization

Important information

Prime numbers are whole numbers that have only two factors (one and itself) and one proper factor (one).

Problem & example

Some examples of prime numbers are 2,3,5,7.

Which of these numbers are prime?

23, 63, 50

Work and solution

23 is prime because it only has 1 and 23 as factors. 63 is not prime, it is composite because it is divisible by 3, 63/3=21. 50 is not prime either because 2x25 is 50 which means it has more than two factors.