Divisor 16183

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

The "Andreas Test" for Divisibility by 16183

To determine if any number is divisible by 16183, apply the "Andreas 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 1094 and subtract this from R.
  3. Take that result and cross off its final digit (units). Take this new number and add 4855 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 16183. That is, your original number is divisible by 16183 if (and only if) Y is. Now that it's much smaller, with basic knowledge of your 16183-times tables, it should be easy to visually see if Y is divisible by 16183. If the Y is still much larger than 16183, the above process can be repeated until it does reduce to within small multiples of 16183.

Easy!