Divisor 6883

Prime Number:
Yes!
Divisibility test:
The "Mark Test"
Test Discovered by:
Matt Parker
Date:
11/11/2024

The "Mark Test" for Divisibility by 6883

To determine if any number is divisible by 6883, apply the "Mark Test":

  1. If your number ("X") has 8 digits or more, separate the last (smallest) 7 digits from the rest. This makes two smaller numbers, call them Left and Right (note: don't add in trailing zeros to L). If there are fewer than 8 digits, L = 0 and therefore R = X.
  2. Multiply L by 999 and subtract this from R.
  3. Take that result and cross off its final digit (units). Take this new number and add 2065 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 6883. That is, your original number is divisible by 6883 if (and only if) Y is. Now that it's much smaller, with basic knowledge of your 6883-times tables, it should be easy to visually see if Y is divisible by 6883. If the Y is still much larger than 6883, the above process can be repeated until it does reduce to within small multiples of 6883.

Easy!