Divisor 17579

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

The "Courtney Pettersen Test" for Divisibility by 17579

To determine if any number is divisible by 17579, apply the "Courtney Pettersen 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 1006 and add to R.
  3. Take that result and cross off its final digit (units). Take this new number and add 1758 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 17579. That is, your original number is divisible by 17579 if (and only if) Y is. Now that it's much smaller, with basic knowledge of your 17579-times tables, it should be easy to visually see if Y is divisible by 17579. If the Y is still much larger than 17579, the above process can be repeated until it does reduce to within small multiples of 17579.

Easy!