posted by makeeda .
which of following is not a prime number?
What do you think? First of all go on to Google and look up prime numbers. You'll get a way better understanding of them in a small amount of time. I'll give you one hint: 51 is a prime number because 3 and 17 are it's factors.
Luv4ever has a typo.
51 is NOT a prime number because 3 and 17 are it's factors.