Divisor 7013

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

The "Analena Kamm Test" for Divisibility by 7013

To determine if any number is divisible by 7013, apply the "Analena Kamm 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 538 and subtract this from R.
  3. Take that result and cross off its final digit (units). Take this new number and add 2104 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 7013. That is, your original number is divisible by 7013 if (and only if) Y is. Now that it's much smaller, with basic knowledge of your 7013-times tables, it should be easy to visually see if Y is divisible by 7013. If the Y is still much larger than 7013, the above process can be repeated until it does reduce to within small multiples of 7013.

Easy!