3) Largest prime factor

The prime factors of 13195 are 5, 7, 13 and 29. What is the largest prime factor of the number 600851475143 ?

by fosco

JavaScript

//prime factorization tree
var largestPrimeFactor = (function (number) {
    var i = 2;

    while (i <= number) {
        if (number % i === 0) {
            number /= i;
        } else {
            ++i;
        }
    }

    return i;
})(600851475143);

console.log(largestPrimeFactor); //6857