Divisor 23773

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

The "Krzysztof Olbiński Test" for Divisibility by 23773

To determine if any number is divisible by 23773, apply the "Krzysztof Olbiński 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 Left and Right (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 1534 and add to R.
  3. Take that result and cross off its final digit (units). Take this new number and add 7132 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 23773. That is, your original number is divisible by 23773 if (and only if) Y is. Now that it's much smaller, with basic knowledge of your 23773-times tables, it should be easy to visually see if Y is divisible by 23773. If the Y is still much larger than 23773, the above process can be repeated until it does reduce to within small multiples of 23773.

Easy!