Set of divisors function

Function

definiendum $ \mathrm{divisors}:\mathbb N^+\to\mathcal{P}(\mathbb N) $
definiendum $ \mathrm{divisors}(n):=\{a\ |\ \exists (b\in\mathbb N).\ a\cdot b=n\} $
make this into a set

Code

A related Boolean function is 

divides :: Integral a => a -> a -> Bool
divides d n = rem n d == 0

Subset of

Function

Requirements

Natural numbers