Divisor 15723

To determine if any number is divisible by 15723, you must apply 2 tests successively. If all of them 'pass' - that is, if your number is divisible by 9 and 1747 - then it is divisible by 15723.

The following tests must pass:

• Test if a number is divisible by 9
• The "Robert Petrie Test" for Divisibility by 1747

Easy!