Divisor 19917

To determine if any number is divisible by 19917, you must apply 2 tests successively. If all of them 'pass' - that is, if your number is divisible by 9 and 2213 - then it is divisible by 19917.

The following tests must pass:

• Test if a number is divisible by 9
• The "Andrew Gilbey Test" for Divisibility by 2213

Easy!