Divisor 21213

To determine if any number is divisible by 21213, you must apply 2 tests successively. If all of them 'pass' - that is, if your number is divisible by 9 and 2357 - then it is divisible by 21213.

The following tests must pass:

• Test if a number is divisible by 9
• The "Bruce Davis Test" for Divisibility by 2357

Easy!