Divisor 20573

To determine if any number is divisible by 20573, you must apply 2 tests successively. If all of them 'pass' - that is, if your number is divisible by 7 and 2939 - then it is divisible by 20573.

The following tests must pass:

• Test if a number is divisible by 7
• The "Pierre D. Test" for Divisibility by 2939

Easy!