Divisor 17293

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

The "JJ Test" for Divisibility by 17293

To determine if any number is divisible by 17293, apply the "JJ 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 2311 and subtract this from R.
  3. Take that result and cross off its final digit (units). Take this new number and add 5188 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 17293. That is, your original number is divisible by 17293 if (and only if) Y is. Now that it's much smaller, with basic knowledge of your 17293-times tables, it should be easy to visually see if Y is divisible by 17293. If the Y is still much larger than 17293, the above process can be repeated until it does reduce to within small multiples of 17293.

Easy!