Divisor 11941

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

The "Elnath Test" for Divisibility by 11941

To determine if any number is divisible by 11941, apply the "Elnath Test":

  1. If your number ("X") has 10 digits or more, separate the last (smallest) 9 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 10 digits, L = 0 and therefore R = X.
  2. Multiply L by 955 and add to R.
  3. Take that result and cross off its final digit (units). Take this new number and subtract 1194 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 11941. That is, your original number is divisible by 11941 if (and only if) Y is. Now that it's much smaller, with basic knowledge of your 11941-times tables, it should be easy to visually see if Y is divisible by 11941. If the Y is still much larger than 11941, the above process can be repeated until it does reduce to within small multiples of 11941.

Easy!