関連ワード:  sum of a number in python    sum of a given number in python    sum digits of a number in python    sum of digits of a number in python using for loop    sum of digits of a number in python using while loop    sum of digits of a number in python using function    sum of digits of a number in python using recursion    sum of digits of a number in python without using function    sum of digits of a number in python without loop    sum of factors of a number in python