# Largest prime factor

*Author: Eric Hodges*

https://projecteuler.net/problem=3

The prime factors of 13195 are 5, 7, 13 and 29.

What is the largest prime factor of the number 600851475143 ?

Source code: prob003-eric256.pl

use v6; sub is_prime ($num) { for (2..^$num) { return 0 unless $num % $_; } return 1; }; class Primes { has $.current = 0; method next { $!current++; $!current++ until is_prime($.current); return $.current; } } my $prime = Primes.new(); my $number = 600851475143; my @primes = gather while ($number > 1) { if !($number % $prime.next) { $number /= $prime.current; take $prime.current; } } say @primes.max;