Divisor 14897

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

The "Peter Test" for Divisibility by 14897

To determine if any number is divisible by 14897, apply the "Peter Test":

  1. If your number ("X") has 11 digits or more, separate the last (smallest) 10 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 11 digits, L = 0 and therefore R = X.
  2. Multiply L by 1428 and add to R.
  3. Take that result and cross off its final digit (units). Take this new number and subtract 4469 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 14897. That is, your original number is divisible by 14897 if (and only if) Y is. Now that it's much smaller, with basic knowledge of your 14897-times tables, it should be easy to visually see if Y is divisible by 14897. If the Y is still much larger than 14897, the above process can be repeated until it does reduce to within small multiples of 14897.

Easy!