reverse a binary number code example

Example: reverse binary representation of a number

long long reversedBits(long long X) {
    long long p = 1;
    long long ans = 0;
    while(X>0){
        int last_bit = (X&1);
        ans = ans + p*last_bit;
        p = p*10;
        X=X>>1;
    }
    return ans;
}