#include <bits/stdc++.h>
using namespace std;
using i64 = long long;
#define N 200005

int cal(int x)
{
    int res = 2;
    for (int i = 2; i * i <= x; i++)
    {
        if (x % i == 0)
        {
            res++;
            if (i * i != x)
                res++;
        }
    }
    return res;
}
i64 mypow(int x, int y)
{
    i64 res = 1;
    while (y--)
        res *= x;
    return res;
}
int cal1(i64 z, int y)
{
    int l = 2, r = 1e9, mid;
    while (l < r)
    {
        mid = l + r + 1 >> 1;
        if (mid > z || powl(mid, y) > z)
            r = mid - 1;
        else
        {
            i64 tmp = mypow(mid, y);
            if (tmp <= z)
                l = mid;
            else
                r = mid - 1;
        }
    }
    if (mypow(l, y) != z)
        return -1;
    else
        return l;
}
void solve()
{
    i64 x;
    cin >> x;
    for (int i = 60; i >= 2; i--)
    {
        int y = cal1(x, i);
        if (y == -1)
            continue;
        int z = cal(y);
        if (mypow(y, z) == x)
        {
            cout << y << '\n';
            return;
        }
    }
    if (x == 1)
        cout << 1;
    else
        cout << -1;
    cout << '\n';
}
signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int t = 1;
    // cin >> t;
    while (t--)
        solve();
}