import random

def sort_digits(number):
    """ Sort the digits of a number
    >>> sort_digits(123)
    123
    >>> sort_digits(321)
    123
    >>> sort_digits(231)
    123
    """
    digits_list = [int(c) for c in str(number)]
    # DEMO 1
    sorted_list = sorted(digits_list)
    # DEMO 2
    #sorted_list = my_sorter(digits_list)
    sorted_number = sum([ (10**(len(sorted_list) - (i+1)))*sorted_list[i] for i in range(len(sorted_list))])
    return sorted_number

def my_sorter(lst):
   if len(lst) < 2:
        return lst
   my_sorted = my_sorter(lst[1:])
   if lst[0] < my_sorted[0]:
      return [lst[0]] + my_sorted
   elif lst[0] > my_sorted[0]:
      return [my_sorted[0]] + my_sorter([lst[0]] + my_sorted[1:])
   else:
      return [lst[0]] + my_sorter

def random_number():
   return random.randint(0, 2147483647)