Sum of digits in C#

Question

What's the fastest and easiest to read implementation of calculating the sum of digits?

I.e. Given the number: 17463 = 1 + 7 + 4 + 6 + 3 = 21

Answer 1

You could do it arithmetically, without using a string:

sum = 0; while (n != 0) {     sum += n % 10;     n /= 10; } 

Answer 2

I use

int result = 17463.ToString().Sum(c => c - '0'); 

It uses only 1 line of code.