Common Fractions

from functools import reduce
from math import sqrt


def is_fraction(of):
    return lambda n: of % n == 0


def fractions(val):
    lst = list(filter(is_fraction(val), range(2, int(sqrt(val)) + 1)))
    return set(lst + list(map(div(val), lst)))


def intersect(a, b):
    return a.intersection(b)


def div(n):
    return lambda x: int(n / x)


def common(*a):
    return sorted(reduce(intersect, [fractions(x) for x in a]))


print(common(512, 1024))