Divisor 1433

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

The "Ronny Moser Test" for Divisibility by 1433

To determine if any number is divisible by 1433, apply the "Ronny Moser Test":

  1. If your number ("X") has 5 digits or more, separate the last (smallest) 4 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 5 digits, L = 0 and therefore R = X.
  2. Multiply L by 31 and subtract this from R.
  3. Take that result and cross off its final digit (units). Take this new number and add 430 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 1433. That is, your original number is divisible by 1433 if (and only if) Y is. Now that it's much smaller, with basic knowledge of your 1433-times tables, it should be easy to visually see if Y is divisible by 1433. If the Y is still much larger than 1433, the above process can be repeated until it does reduce to within small multiples of 1433.

Easy!