I tried to solve the problem 1475A - Нечетный делитель, Where the problem is rather simple we have to check if a number is a power of 2 if true then print NO and if false then YES.It was solved but I thought if I could find if a number x is power of y for long long numbers.So, I wrote the following function:

bool isPowerofN(long long num, long long base)
{
    double log_num = (log(num) / log(base));
    int x = floor(log_num);
    int y = ceil(log_num);
    if (x == y)
        return true;
    else
        return false;
}

The result are correct in my device(mac m1-gcc (Homebrew GCC 11.2.0_3) 11.2.0)

But when submit the code it gives error for larger numbers like 10^40=1099511627776. Here is the submission : 169948113 It should output NO but give YES instead.

So, is there a problem with the implementation or is there another way to check this in constant time ?