Divisor 9981

To determine if any number is divisible by 9981, you must apply 2 tests successively. If all of them 'pass' - that is, if your number is divisible by 9 and 1109 - then it is divisible by 9981.

The following tests must pass:

• Test if a number is divisible by 9
• The "Gyrdon Test" for Divisibility by 1109

Easy!