Divisor 5843

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

The "DrAmi Test" for Divisibility by 5843

To determine if any number is divisible by 5843, apply the "DrAmi Test":

  1. If your number ("X") has 10 digits or more, separate the last (smallest) 9 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 10 digits, L = 0 and therefore R = X.
  2. Multiply L by 235 and subtract this from R.
  3. Take that result and cross off its final digit (units). Take this new number and add 1753 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 5843. That is, your original number is divisible by 5843 if (and only if) Y is. Now that it's much smaller, with basic knowledge of your 5843-times tables, it should be easy to visually see if Y is divisible by 5843. If the Y is still much larger than 5843, the above process can be repeated until it does reduce to within small multiples of 5843.

Easy!