Project Euler Problem 3

#! /usr/bin/ruby

def prime? n
  (2..(n-1)).each { |x| return false if n % x == 0 }
  true
end

def euler_3(n)
  i = 2
  numbers = []
  sum = 1

  while sum < n
    if n % i == 0 && prime?(i)
      numbers << i
      sum *= i
    end
    i += 1
  end
  puts "The answer is #{numbers.last}"
end

n = ARGV[0].to_i
euler_3 n