Divisor 1481

Prime Number:
Yes!
Divisibility test:
The "Jean-Pierre Namink Test"
Test Discovered by:
Matt Parker
Date:
11/11/2024

The "Jean-Pierre Namink Test" for Divisibility by 1481

To determine if any number is divisible by 1481, apply the "Jean-Pierre Namink 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 82 and subtract this from R.
  3. Take that result and cross off its final digit (units). Take this new number and subtract 148 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 1481. That is, your original number is divisible by 1481 if (and only if) Y is. Now that it's much smaller, with basic knowledge of your 1481-times tables, it should be easy to visually see if Y is divisible by 1481. If the Y is still much larger than 1481, the above process can be repeated until it does reduce to within small multiples of 1481.

Easy!