sum of number's caracters

[perfringo]

To give you some ideas: there are simple ways to sum digits in number.

For strings ('give me character converted into int for every character in string and sum'):

>>> s = '123456'
>>> sum(int(char) for char in s)
21

For integer 'add reminder to total until there is no floor':

>>> num = 123456
>>> total = 0
>>> while num:
...     num, reminder = divmod(num, 10)
...     total += reminder
... 
>>> total
21