Divisor 21967

To determine if any number is divisible by 21967, you must apply 2 tests successively. If all of them 'pass' - that is, if your number is divisible by 11 and 1997 - then it is divisible by 21967.

The following tests must pass:

• Test if a number is divisible by 11
• The "Robert Wilson Test" for Divisibility by 1997

Easy!