Divisor 3994

To determine if any number is divisible by 3994, you must apply 2 tests successively. If all of them 'pass' - that is, if your number is divisible by 2 and 1997 - then it is divisible by 3994.

The following tests must pass:

• Test if a number is divisible by 2
• The "Robert Wilson Test" for Divisibility by 1997

Easy!