It is easy to take prime number 2 (from the famous treatise A Short Table of Even Primes) and "divide it into" 6. And it is easy to take 6 and factor it into primes 2 and 3.

Where the OP wrote

> Those numbers you can’t divide into other numbers, except when you divide them by themselves or 1?

would have read better with

"Those numbers you can't factor into ..."

I.e., it is easy to take 2 and "divide it into 6" but can't factor 2 into a product of other numbers except itself and 1.