What are the primes for 51

3 and 17

Step-by-step explanation:

The list of all positive divisors (i. e., the list of all integers that divide 51) is as follows: 1, 3, 17, 51.

To be 51 a prime number, it would have been required that 51 has only two divisors, i. e., itself and 1.

As a consequence:

51 is a multiple of 1

51 is a multiple of 3

51 is a multiple of 17

To be 51 a prime number, it would have been required that 51 has only two divisors, i. e., itself and 1.

However, 51 is a semiprime (also called biprime or 2-almost-prime), because it is the product of a two non-necessarily distinct prime numbers. Indeed, 51 = 3 x 17, where 3 and 17 are both prime numbers.