A prime number is a number that has no other factors except 1 and itself. For example, the number 12 can be broken down into 1x12, 2x6, and 3x4, therefore 12 is not a prime number. However, the number 13 has no other factors except 1x13, therefore it IS a prime number. To answer this question, 19 and 19 could be used. Or 31 and 7. Or 33 and 5.