Prime factorization of 39

Lets quickly run through the prime numbers and see what it is not divisible by

39 is not divisible by 2

39 IS divisible by 3

So lets stop right here.

What is 39 divided by 3? 13!

And 13 is a prime number too!

So that is all we can do.

So prime factorization of 39 is 3 x 13