Divisor 20813

To determine if any number is divisible by 20813, you must apply 2 tests successively. If all of them 'pass' - that is, if your number is divisible by 13 and 1601 - then it is divisible by 20813.

The following tests must pass:

• Test if a number is divisible by 13
• The "Lucas Höhne Test" for Divisibility by 1601

Easy!