Divisor 3125

To determine if any number is divisible by 3125, apply this test:

1. Ignore everything except the 5 right-most digits. Every larger digit than these is irrelevant because 10⁵ is divisible by 3125.
2. The number should now be small enough to be able to deduce divisibility by 3125 with basic application of your 3125-times tables!

Easy!