#include <bits/stdc++.h>
#define endl '\n'
#define all(x) x.begin(),x.end()
#define x first
#define y second
#define pb push_back
#define ppb pop_back
#define pf push_front
#define ppf pop_front
#define ll long long
#define ld long double
#define int ll
#define ii pair<int, int>
#define iii pair<int, ii>
#define vi vector<int>
using namespace std;
const int ms = 2e6+100;
const int sigma = 30;
const ll mod = 1e9+7;

int perfect_sum[ms];
int ans[ms];

void sieve() {
  for(int i = 1; i < ms; i++) {
    for(int j = i; j < ms; j += i)
      perfect_sum[j]+=i;
  }
  int best = -1;
  ans[0] = best;
  for(int i=1; i<ms; i++){
    if(perfect_sum[i]==i+i)
      best = i;
    ans[i] = best;
  }
}

int32_t main(){
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  sieve();
  int n, a;
  cin>>n;
  while(n--){
    cin>>a;
    cout<<ans[a]<<endl;
  }
}