Optimize pow(x, n) + pow(y, n) == pow(z, n)

I'm having a go at the xⁿ + yⁿ = zⁿ problem and want to see how fast I can make it go and if I can get a result but I cant figure out how to make my code vectorize or parallelize:

#include <iostream>
using namespace std;

int main(){
    unsigned long n = 0;
    cout << "n = ";
    cin >> n;
    for(unsigned long x = 1; x < 0xffffffff; ++x){
        cout << "x = "<< x << "\n";
        for(unsigned long y = 2; y < 0xffffffff; ++y){
            const unsigned long xy = pow(x, n) + pow(y, n);
            cout << "y = "<< y << "\n";
            for(unsigned long z = 1; z < 0xffffffff; ++z){
                if(xy == pow(z, n)) cout << x << "n + "<< y << "n = "<< z << "n\n";
            }
        }
    }
}

the optimization diagnostic gives 15523

I'm using Intel C++ compiler 18.0