Re:
https://www.mathsisfun.com/numbers/prim ... o-10k.html

A number is not a prime number if ending 0,2,4,5,6, or 8 (except 2,5)
Of remaining numbers, it's not prime if evenly divisible by 3,5,7,9,11, or 13

589 selects as a prime number (it's not) ... unless divided by 19
Maybe this is the better selection (if divisor is not the number):
"not prime if evenly divisible by 3,5,7,9,11,13,15,17, or 19"
since "prime if divisible by itself and 1" is still a rule.

3589 hints that a divisor selection list is required:
3,5,7,9,11,13,15,17,19,21,23,25,27,29,31,33,35,37, ...
with divisors required related to size of number.
Rod
