class Integer
  def divisors
    divisors = []
    (1..Math.sqrt(self).to_i).each do |num|
      if self % num == 0
        divisors << num
        divisors << self / num
      end
    end
    divisors
  end
end

triangle = Enumerator.new do |y|
  sum = 1
  next_num = 2
  loop do
    y << sum
    sum += next_num
    next_num += 1
  end
end

val = triangle.next

while val.divisors.count < 500
  val = triangle.next
end

puts val