Divisor 27883

To determine if any number is divisible by 27883, apply this test:

1. If your number ("X") has 7 digits or more, separate the last (smallest) 6 digits from the rest. This makes two smaller numbers, call them L^eft and R^ight (note: don't add in trailing zeros to L). If there are fewer than 7 digits, L = 0 and therefore R = X.
2. Multiply L by 3788 and subtract this from R.
3. Take that result and cross off its final digit (units). Take this new number and add 8365 times the digit you just crossed off. Call this final result "Y".
4. Y will be much smaller than X, but we have preserved divisibility by 27883. That is, your original number is divisible by 27883 if (and only if) Y is. Now that it's much smaller, with basic knowledge of your 27883-times tables, it should be easy to visually see if Y is divisible by 27883. If the Y is still much larger than 27883, the above process can be repeated until it does reduce to within small multiples of 27883.

Easy!