342. Power of Four

Given an integer (signed 32 bits), write a function to check whether it is a power of 4.

Example:
Given num = 16, return true. Given num = 5, return false.

Follow up: Could you solve it without loops/recursion?

/**
 * @param {number} num
 * @return {boolean}
 */
var isPowerOfFour = function(num) {
    if (((Math.log(num)/Math.log(4))%1)===0) 
        return true;
    else 
        return false;
};