function run_factorize(n) {
    if (n <= 3)
        return [n];

    var ans = [];
    var done = false;
    while (!done) {
        if (n % 2 === 0) {
            ans.push(2);
            n /= 2;
            continue;
        }
        if (n % 3 === 0) {
            ans.push(3);
            n /= 3;
            continue;
        }
        if (n === 1)
            return ans;
        var sr = Math.sqrt(n);
        done = true;
        // try to divide the checked number by all numbers till its square root.
        for (var i = 6; i <= (sr + 6); i += 6) {
            if (n % (i - 1) === 0) { // is n divisible by i-1?
                ans.push((i - 1));
                n /= (i - 1);
                done = false;
                break;
            }
            if (n % (i + 1) === 0) { // is n divisible by i+1?
                ans.push((i + 1));
                n /= (i + 1);
                done = false;
                break;
            }
        }
    }
    ans.push(n);
    return ans;
}