#include "bits/extc++.h"

using namespace std;

template <typename T, typename... U>
void dbgh(const T& t, const U&... u) {
    cerr << t;
    ((cerr << " | " << u), ...);
    cerr << endl;
}

#ifdef DEBUG
#define dbg(...)                                           \
    cerr << "L" << __LINE__ << " [" << #__VA_ARGS__ << "]" \
         << ": ";                                          \
    dbgh(__VA_ARGS__)
#else
#define cerr   \
    if (false) \
    cerr
#define dbg(...)
#endif

#define endl "\n"
#define long int64_t
#define sz(x) int(std::size(x))

long ipow(long x, int exp) {
    if (x == 0) {
        return 0;
    } else if (x < 0) {
        return -10;
    }
    long ans = 1;

    for (int i = 0; i < exp; i++) {
        if (long(2e18) / x < ans) {
            ans = 2e18;
        } else {
            ans *= x;
        }
    }

    return ans;
}

long inpow(long x, int m) {
    long cx = pow(x, double(1) / m);

    for (long test = cx - 2; test <= cx + 2; test++) {
        if (ipow(test, m) == x) {
            return test;
        }
    }

    return -1;
}

vector<pair<int, int>> factor(int x) {
    vector<pair<int, int>> ans;

    for (int p = 2; p * p <= x; p++) {
        if (x % p) {
            continue;
        }

        int e = 0;
        while (x % p == 0) {
            x /= p;
            e++;
        }
        ans.emplace_back(p, e);
    }

    if (x > 1) {
        ans.emplace_back(x, 1);
    }

    return ans;
}

vector<pair<int, int>> do_factor(long x) {
    for (int m = 70; m >= 2; m--) {
        long cbase = inpow(x, m);
        if (cbase == -1) {
            continue;
        }

        auto cf = factor(cbase);
        for (auto& [_p, e] : cf) {
            e *= m;
        }
        return cf;
    }

    return {};
}

template <typename Cb>
void dfs_f(const vector<pair<int, int>>& facts,
           int ind,
           vector<pair<int, int>>& out,
           const Cb& cb) {
    if (ind == sz(facts)) {
        cb(out);
        return;
    }

    out.emplace_back(facts[ind]);
    for (int i = 0; i <= facts[ind].second; i++) {
        out[ind].second = i;
        dfs_f(facts, ind + 1, out, cb);
    }
    out.pop_back();
}

long eval(const vector<pair<int, int>>& fact) {
    long ans = 1;
    for (auto& [p, e] : fact) {
        ans *= ipow(p, e);
    }
    return ans;
}

void solve() {
    long x;
    cin >> x;

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

    auto facts = do_factor(x);
    if (!sz(facts)) {
        cout << -1 << endl;
        return;
    }
    for (auto& [p, e] : facts) {
        dbg(p, e);
    }

    long ans = 2e18;
    vector<pair<int, int>> out;
    dfs_f(facts, 0, out, [&](const auto&) -> void {
        auto nf = out;
        long divs = 1;
        for (auto& [_p, e] : nf) {
            divs *= e + 1;
        }
        for (auto& [_p, e] : nf) {
            e *= divs;
        }
        dbg(eval(out), divs);
        if (nf == facts) {
            dbg("A");
            ans = min(ans, eval(out));
        }
    });

    if (ans > x) {
        cout << -1 << endl;
    } else {
        cout << ans << endl;
    }
}

int main() {
    cin.tie(nullptr);
    cin.exceptions(ios::failbit);
    ios_base::sync_with_stdio(false);
    solve();
}