Divisor 6621

To determine if any number is divisible by 6621, you must apply 2 tests successively. If all of them 'pass' - that is, if your number is divisible by 3 and 2207 - then it is divisible by 6621.

The following tests must pass:

• Test if a number is divisible by 3
• The "Stef Siekman Test" for Divisibility by 2207

Easy!