Divisor 1563

To determine if any number is divisible by 1563, you must apply 2 tests successively. If all of them 'pass' - that is, if your number is divisible by 3 and 521 - then it is divisible by 1563.

The following tests must pass:

• Test if a number is divisible by 3
• Test if a number is divisible by 521

Easy!