func_code_string: #include <bits/stdc++.h>   using namespace std;      const int N = (int) 1e7 + 100;      long long s[N];   int d[N];   int ans[N];      int main() {     fill(d, d + N, -1);     d[1] = 1;     for (int i = 2; i * i < N; i++) {       if (d[i] == -1) {         d[i] = i;         for (int j = i * i; j < N; j += i) {           if (d[j] == -1) {             d[j] = i;           }         }       }     }     s[1] = 1;     for (int i = 2; i < N; i++) {       if (d[i] == -1) {         d[i] = i;         s[i] = i + 1;       } else {         int j = i;         s[i] = 1;         while (j % d[i] == 0) {           j /= d[i];           s[i] = s[i] * d[i] + 1;         }         s[i] *= s[j];       }     }     fill(ans, ans + N, -1);     for (int i = N - 1; i > 0; i--) {       if(s[i]<N){  // avoiding overflow.       ans[s[i]] = i;      }                     }     int tests;     cin >> tests;     while (tests-- > 0) {       int c;       cin >> c;       cout << ans[c] << endl;     }     return 0;   }   