# Prime decomposition

*Author: Salve J. Nilsen*

The prime decomposition of a number is defined as a list of prime numbers which when all multiplied together, are equal to that number.

Example: 12 = 2 × 2 × 3, so its prime decomposition is {2, 2, 3}

# Task

Write a function which returns an array or collection which contains the prime decomposition of a given number, n, greater than 1. If your language does not have an isPrime-like function available, you may assume that you have a function which determines whether a number is prime (note its name before your code).

# More

http://rosettacode.org/wiki/Prime_decomposition#Perl_6

Source code: prime-decomposition.pl

use v6; my @primes = 2, 3, 5, -> $n is copy { repeat { $n += 2 } until $n %% none @primes ... { $_ * $_ >= $n } $n; } ... *; sub factors(Int $remainder is copy) { return 1 if $remainder <= 1; gather for @primes -> $factor { if $factor * $factor > $remainder { take $remainder if $remainder > 1; last; } # How many times can we divide by this prime? while $remainder %% $factor { take $factor; last if ($remainder div= $factor) === 1; } } } say "{factors 536870911}";