Divisor 16649

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

The "Vanessa Clark Test" for Divisibility by 16649

To determine if any number is divisible by 16649, apply the "Vanessa Clark Test":

  1. If your number ("X") has 6 digits or more, separate the last (smallest) 5 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 6 digits, L = 0 and therefore R = X.
  2. Multiply L by 106 and add to R.
  3. Take that result and cross off its final digit (units). Take this new number and add 1665 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 16649. That is, your original number is divisible by 16649 if (and only if) Y is. Now that it's much smaller, with basic knowledge of your 16649-times tables, it should be easy to visually see if Y is divisible by 16649. If the Y is still much larger than 16649, the above process can be repeated until it does reduce to within small multiples of 16649.

Easy!