Divisor 12591

To determine if any number is divisible by 12591, you must apply 2 tests successively. If all of them 'pass' - that is, if your number is divisible by 9 and 1399 - then it is divisible by 12591.

The following tests must pass:

• Test if a number is divisible by 9
• The "N T Test" for Divisibility by 1399

Easy!