#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <map>
#include <queue>
#include <set>
const int OO = 0;
const int md = 998244353;
typedef long long ll;
typedef unsigned long long ull;
using namespace std;

ll gcd(ll x, ll y) {
	x = max(x, y);
	y = min(x, y);
	ll z;
	while (y > 0) {
		z = x;
		x = y;
		y = z % y;
	}
	return x;
}

const ll INF = 2e18;

ll pw(ll b, ll e) {
	ll res = 1;
	while (e--) {
		if (res > INF / b) return INF;
		res *= b;
	}
	return res;
}

ll root(ll x, int k) {
	ll lo = 1, hi = x, mid;
	while (lo < hi) {
		mid = (lo + hi) / 2;
		ll p = pw(mid, k);
		if (p == x) return mid;
		if (p < x) lo = mid + 1;
		else hi = mid;
	}
	if (pw(lo, k) == x) return lo;
	return INF;
}

int num_factors(ll x) {
	int ans = 0;
	for (int i = 1; i * i <= x; i++) {
		if (x % i == 0)
			if (i * i == x)
				ans++;
			else
				ans += 2;
	}
	return ans;
}

void solve() {
	ll x;
	cin >> x;
	if (x == 1) {
		cout << 1 << endl;
		return;
	}
	if (x == 2) {
		cout << -1 << endl;
		return;
	}
	for (int k = 70; k >= 2; k--) {
		ll p = root(x, k);
		if (p == INF) continue;
		if (num_factors(p) == k) {
			cout << p << endl;
			return;
		}
	}
	cout << -1 << endl;
}

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	int tests = 1;
	//cin >> tests;
	while (tests--) solve();
}