#include <bits/stdc++.h>
using namespace std;
const int N=1013,mod=998244353;
typedef long long ll;
typedef long double ld;
int input=0;
const ll inf=2e18;
ll poww(ll x,int p){
    ll rt=1;
    for(int i=1;i<=p;i++)if(inf/x<=rt)rt=inf;else rt*=x;
    return rt;
}
int get(ll x){
    int rt=0;
    for(int i=1;i*i<=x;i++){
        if(x%i==0)rt+=2;
        if(i*i==x)rt--;
    }return rt;
}
void solve(){
    ll n;
    cin>>n;
    if(n==1){
        cout<<1<<'\n';
        return;
    }
    for(int pw=60;pw>=2;pw--){
        ll l=1,r=1e9,ans=0;
        while(l<=r){
            ll mid=(l+r)/2;
            if(poww(mid,pw)>n)r=mid-1;
            else ans=mid,l=mid+1;
        }
        if(poww(ans,pw)!=n)continue;
        if(get(ans)!=pw)continue;
        cout<<ans<<'\n';
        return;
    }
    cout<<-1<<'\n';
}

int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    cout<<fixed<<setprecision(10);
    int T;
    if(input)cin>>T;else T=1;
    for(int tc=1;tc<=T;tc++)solve();
}