Divisor 1451

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

The "Lukáš Test" for Divisibility by 1451

To determine if any number is divisible by 1451, apply the "Lukáš Test":

  1. If your number ("X") has 9 digits or more, separate the last (smallest) 8 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 9 digits, L = 0 and therefore R = X.
  2. Multiply L by 18 and subtract this from R.
  3. Take that result and cross off its final digit (units). Take this new number and subtract 145 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 1451. That is, your original number is divisible by 1451 if (and only if) Y is. Now that it's much smaller, with basic knowledge of your 1451-times tables, it should be easy to visually see if Y is divisible by 1451. If the Y is still much larger than 1451, the above process can be repeated until it does reduce to within small multiples of 1451.

Easy!