Divisor 5779

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

The "Diarya Test" for Divisibility by 5779

To determine if any number is divisible by 5779, apply the "Diarya Test":

  1. If your number ("X") has 9 digits or more, separate the last (smallest) 8 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 9 digits, L = 0 and therefore R = X.
  2. Multiply L by 184 and add to R.
  3. Take that result and cross off its final digit (units). Take this new number and add 578 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 5779. That is, your original number is divisible by 5779 if (and only if) Y is. Now that it's much smaller, with basic knowledge of your 5779-times tables, it should be easy to visually see if Y is divisible by 5779. If the Y is still much larger than 5779, the above process can be repeated until it does reduce to within small multiples of 5779.

Easy!