Divisor 15421

To determine if any number is divisible by 15421, you must apply 2 tests successively. If all of them 'pass' - that is, if your number is divisible by 7 and 2203 - then it is divisible by 15421.

The following tests must pass:

• Test if a number is divisible by 7
• The "Acid DotCom Test" for Divisibility by 2203

Easy!