#include <iostream>
using namespace std;

#include <atcoder/modint>
using mint = atcoder::modint998244353;

using lint = long long;

mint solve(lint N, lint S) {
    auto binom = [&](lint n, lint r) -> mint {
        if (n < 0 or r < 0 or r > n) return 0;
        mint num = 1, den = 1;
        r = std::min(r, n - r);
        for (lint i = 0; i < r; ++i) {
            num *= n - i;
            den *= i + 1;
        }
        return num / den;
    };

    mint ret = 1;

    {
        lint cur = N;
        for (int p = 2; cur > 1; ++p) {

            int deg = 0;
            while (cur % p == 0) {
                cur /= p;
                ++deg;
            }

            mint tmp = 0, b = 1;

            if (!deg) continue;

            for (int d = 0; d <= deg; ++d) {
                tmp += binom(deg - d + S - 2, S - 2) * b;
                b *= p;
            }

            ret *= tmp;
        }
    }

    return ret * S;
}

int main() {
    cin.tie(nullptr)->sync_with_stdio(false);

    int T;
    cin >> T;
    while (T--) {
        lint N, S;
        cin >> N >> S;
        cout << solve(N, S).val() << '\n';
    }
}