num_as_sortable_string.py

def number_to_string(number, words):
    list_out = []
	if not number:
		return words[0] # Because 0 is '0', not ''.
    while number:
        list_out = [number % len(words)] + list_out
        number = number // len(words)
    return ''.join(words[n] for n in list_out)

def number_to_zpadded_string(number, length=32):
    return number_to_string(number, 'abcdefghijklmnopqrstuvwxy').ljust(
		length, 'z')