Divisor 25759

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

The "Pi Test" for Divisibility by 25759

To determine if any number is divisible by 25759, apply the "Pi Test":

  1. If your number ("X") has 6 digits or more, separate the last (smallest) 5 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 6 digits, L = 0 and therefore R = X.
  2. Multiply L by 3036 and subtract this from R.
  3. Take that result and cross off its final digit (units). Take this new number and add 2576 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 25759. That is, your original number is divisible by 25759 if (and only if) Y is. Now that it's much smaller, with basic knowledge of your 25759-times tables, it should be easy to visually see if Y is divisible by 25759. If the Y is still much larger than 25759, the above process can be repeated until it does reduce to within small multiples of 25759.

Easy!