Prime Factors

                function largestPrimeFactor(n) {
                    let factor = 2;
                    let maxFactor = 1;
                
                    while (n % factor === 0) {
                        maxFactor = factor;
                        n /= factor;
                    }
                
                    factor = 3;
                    while (factor * factor <= n) {
                        if (n % factor === 0) {
                            maxFactor = factor;
                            n /= factor;
                        } else {
                            factor += 2;
                        }
                    }
                
                    if (n > 1) {
                        maxFactor = n;
                    }
                
                    return maxFactor;
                }
                console.log(largestPrimeFactor(600851475143));