Divisor 20791

To determine if any number is divisible by 20791, you must apply 2 tests successively. If all of them 'pass' - that is, if your number is divisible by 17 and 1223 - then it is divisible by 20791.

The following tests must pass:

• Test if a number is divisible by 17
• The "Frans Test" for Divisibility by 1223

Easy!