1) I'm confused by the examples

1) I'm confused by the examples. If

checkio(17) == 0
checkio(33) == 0

are zero. Why isn't

checkio(5) == 5

?

2) If the solution is to be found in

(or numbers divided at non one digit prime number)

, then I don't get what this sentence is supposed to mean. That#s a sentence that could use some good hyphenation to make thins a little clearer.