Divisor 9987

To determine if any number is divisible by 9987, you must apply 2 tests successively. If all of them 'pass' - that is, if your number is divisible by 3 and 3329 - then it is divisible by 9987.

The following tests must pass:

• Test if a number is divisible by 3
• The "Fergus Test" for Divisibility by 3329

Easy!