Divisor 12009

To determine if any number is divisible by 12009, you must apply 2 tests successively. If all of them 'pass' - that is, if your number is divisible by 3 and 4003 - then it is divisible by 12009.

The following tests must pass:

• Test if a number is divisible by 3
• The "Filip Sowa Test" for Divisibility by 4003

Easy!