Divisor 21003

To determine if any number is divisible by 21003, you must apply 2 tests successively. If all of them 'pass' - that is, if your number is divisible by 3 and 7001 - then it is divisible by 21003.

The following tests must pass:

• Test if a number is divisible by 3
• The "William Evans Test" for Divisibility by 7001

Easy!