#include <bits/stdc++.h>
#define pb push_back
#define mp make_pair
#define x first
#define y second

using namespace std;

typedef long double ld;
typedef long long ll;

const int MAX_BOUND = (int) 1e6;
const ll INF = (ll) 1e18;

int main()
{
 	//freopen("input.txt", "r", stdin);
 	//freopen("output.txt", "w", stdout);
	ios_base::sync_with_stdio(0); cin.tie(0);

	ll x;
	cin >> x;
	if (x == 1) cout << "1\n", exit(0);

	ll answer = INF + 1;
	for (int step = 2; step < 60; step++)
	{
	 	ll lef = 1, rig = INF;
	 	while (lef + 1 < rig)
	 	{
	 	 	ll mid = (lef + rig) / 2;

	 	 	ll cur = 1;
	 	 	bool full = false;
	 	 	for (int i = 1; i <= step; i++)
	 	 	{
	 	 		if (cur > x / mid) full = true;
	 	 		else cur *= mid;
	 	 	}

	 	 	if (full || cur >= x) rig = mid;
	 	 	else lef = mid;
	 	}

	 	ll cur = 1;
	 	bool full = false;
	 	for (int i = 1; i <= step; i++)
	 	{
	 	 	if (cur > x / rig) full = true;
	 	 	else cur *= rig;
	 	}

	 	if (full || cur != x) continue;

	 	int divis = 0;
	 	for (int j = 1; j * j <= rig; j++)
	 	{
	 	 	if (rig % j != 0) continue;
	 	 	divis++;
	 	 	if (j != rig / j) divis++;
	 	}

	 	if (divis == step) answer = min(answer, rig);
	}

	if (answer != INF + 1) cout << answer << '\n';
	else cout << "-1\n";
	return 0;
}