Divisor 2969

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

The "Brad Test" for Divisibility by 2969

To determine if any number is divisible by 2969, apply the "Brad Test":

  1. If your number ("X") has 8 digits or more, separate the last (smallest) 7 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 8 digits, L = 0 and therefore R = X.
  2. Multiply L by 408 and add to R.
  3. Take that result and cross off its final digit (units). Take this new number and add 297 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 2969. That is, your original number is divisible by 2969 if (and only if) Y is. Now that it's much smaller, with basic knowledge of your 2969-times tables, it should be easy to visually see if Y is divisible by 2969. If the Y is still much larger than 2969, the above process can be repeated until it does reduce to within small multiples of 2969.

Easy!