Easily test if any number is evenly divisible by 9
Example
Is 7472916 divisible by 9?
Yes
Step 1
Add together each digit in the number.
7+4+7+2+9+1+6 = 36
Step 2
Divide the result of step 1 by 9
36 / 9 = 4
Step 3
The original number is evenly divisible by 9 if the result of step 2 is a whole number.
Yes