Divisor 1033

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

The "Jaap Test" for Divisibility by 1033

To determine if any number is divisible by 1033, apply the "Jaap Test":

  1. If your number ("X") has 7 digits or more, separate the last (smallest) 6 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 7 digits, L = 0 and therefore R = X.
  2. Multiply L by 56 and add to R.
  3. Take that result and cross off its final digit (units). Take this new number and add 310 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 1033. That is, your original number is divisible by 1033 if (and only if) Y is. Now that it's much smaller, with basic knowledge of your 1033-times tables, it should be easy to visually see if Y is divisible by 1033. If the Y is still much larger than 1033, the above process can be repeated until it does reduce to within small multiples of 1033.

Easy!