Divisor 21689

To determine if any number is divisible by 21689, you must apply 2 tests successively. If all of them 'pass' - that is, if your number is divisible by 529 and 41 - then it is divisible by 21689.

The following tests must pass:

• Test if a number is divisible by 529
• Test if a number is divisible by 41

Easy!