What's a Perfect Power anyway?

DESCRIPTION:

A perfect power is a classification of positive integers:

In mathematics, a perfect power is a positive integer that can be expressed as an integer power of another positive integer. More formally, n is a perfect power if there exist natural numbers m > 1, and k > 1 such that mk = n.

Your task is to check wheter a given integer is a perfect power. If it is a perfect power, return a pair m and k with mk = n as a proof. Otherwise return Nothing, Nil, null, NULL, None or your language's equivalent.

Note: For a perfect power, there might be several pairs. For example 81 = 3^4 = 9^2, so (3,4) and (9,2) are valid solutions. However, the tests take care of this, so if a number is a perfect power, return any pair that proves it.

Examples

isPP(4) => [2,2]
isPP(9) => [3,2]
isPP(5) => None

---

def isPP(n):
    even=False
    if n%2==0:
        even=True
    max=round(n**(1/2))+1
    if even==True:
        for i in range(2,max):
            for j in range(2,max,2):
                if j**i==n:
                    return [j,i]
    else:
        for i in range(2,max):
            for j in range(3,max,2):
                if j**i==n:
                    return [j,i]
    return None