Divisor 21524

To determine if any number is divisible by 21524, you must apply 2 tests successively. If all of them 'pass' - that is, if your number is divisible by 4 and 5381 - then it is divisible by 21524.

The following tests must pass:

• Test if a number is divisible by 4
• The "Joseph Richardson Test" for Divisibility by 5381

Easy!