Power of Three

Given an integer, write a function to determine if it is a power of three.

Follow up: Could you do it without using any loop / recursion?

class Solution(object):
    def isPowerOfThree(self, n):
        """
        :type n: int
        :rtype: bool
        """
        if not n:
            return False
        while n % 3 == 0:
            n /= 3
        return (n == 1)