kata solution

require 'prime'
def factors_of(number)
  primes, powers = number.prime_division.transpose
  exponents = powers.map{|i| (0..i).to_a}
  divisors = exponents.shift.product(*exponents).map do |powers|
    primes.zip(powers).map{|prime, power| prime ** power}.inject(:*)
  end
  divisors.sort.map{|div| [div, number / div]}
end
def sigma1(nmax)
  arr = []

  if( nmax>1 )
    ar0 = factors_of(nmax)
    ar0.each do |x,y|
      arr.push(x)
    end
    arr.inject(0) do |sum,x|
      sum + x
    end
  else
    0
  end
end
def equal_sigma1(nmax)
  limit = nmax
  arr = {}
  sum = 0
  while (nmax>1)
    rev_nmax = nmax.to_s.reverse

    if nmax.to_s != rev_nmax && ( nmax<=limit || rev_nmax.to_i<=limit ) && sigma1( nmax )==sigma1( rev_nmax.to_i )

      if nmax<=limit
        arr[nmax] = nmax
      end
      if rev_nmax.to_i<=limit
        arr[rev_nmax.to_i] = rev_nmax.to_i
      end

    end

    nmax -= 1
  end

  arr.each do |var,v|
    sum += var.to_i
  end
  #sum = 36784
  sum
end