Divisor 4943

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

The "Kat Test" for Divisibility by 4943

To determine if any number is divisible by 4943, apply the "Kat Test":

  1. If your number ("X") has 5 digits or more, separate the last (smallest) 4 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 5 digits, L = 0 and therefore R = X.
  2. Multiply L by 114 and add to R.
  3. Take that result and cross off its final digit (units). Take this new number and add 1483 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 4943. That is, your original number is divisible by 4943 if (and only if) Y is. Now that it's much smaller, with basic knowledge of your 4943-times tables, it should be easy to visually see if Y is divisible by 4943. If the Y is still much larger than 4943, the above process can be repeated until it does reduce to within small multiples of 4943.

Easy!