A recursive function that can check if a number num is power a anohter number base.

bool isPowerof(long long num, long long base)
{
    if (num <= 0)
        return false;
    if (num % base == 0)
        return isPowerof(num / base, base);
    if (num == 1)
        return true;
    return false;
}

This function can show accurate results if the number is num<= $$$2^{62}$$$ and in O($$$log_{base}^{num}$$$).Here is a sample submission 169977243.