def PSR(primes): return max([product(c) for c in powerset(primes) if product(c) < product(primes) ** (1 / 2)])
def divisors(n): if type(n) == type(0): return {product(a) for a in powerset(factorize(n))} if type(n) in [type(()), type(set())]: return {product(a) for a in powerset(n)}