#include <bits/stdc++.h>
using namespace std;

#define tsolve int t; cin >> t; while(t--) solve
#define debug(x) cerr << __LINE__ << ": "#x" = " << (x) << endl
#define nl '\n'
#define all(x) ::begin(x), ::end(x)
#define sz(x) (int)::size(x)
using ll = long long;
using ld = long double;

constexpr ll INF = 1e18l + 1;
ll x;

ll npow(ll v, ll n) {
	ll r = 1;
	for (ll i = 0; i < n; ++i) {
		if (INF / r < v) return INF;
		r *= v;
	}
	return r;
}

ll nsqrt(ll v, ll n) {
	ll lo = 2;
	ll hi = 1'000'000'000;

	while (lo < hi) {
		ll md = (lo + hi) / 2;
		if (npow(md, n) < v) lo = md + 1;
		else hi = md;
	}

	return lo;
}

ll count_divs(ll v) {
	ll r = 0;

	for (ll i = 1; i * i < v; ++i) {
		if (v % i == 0) r += 2;
	}
	ll t = nsqrt(v, 2);
	if (npow(t, 2) == v) ++r;

	return r;
}

void solve() {
    cin >> x;

	if (x == 1) {
		cout << 1 << nl;
		return;
	}

	ll s;
	ll r = -1;

	for (ll i = 2; true; ++i) {
		s = nsqrt(x, i);
		//cerr << i << ": " << s << ", " << npow(s, i) << nl;
		if (s == 2 && npow(s, i) > x) break;

		if (npow(s, i) != x) {
			continue;
		}

		if (count_divs(s) == i) {
			r = s;
		}
	}

	cout << r << nl;
}
 
int main() {
	cin.tie(0)->sync_with_stdio(false);
	cout << setprecision(16);
	solve();
}