Would you like to check if a number is divisible by some other number?
Remember these handy rules!
The International Divisibility Rules Database is a comprehensive* collection of convenient 'divisibility rules', also known as 'divisibility tests'.
Example:
You're out for a walk on a sunny day and you happen across 270,082,896,488 ducklings. Cute! But how do you know if they can be evenly divided into 1009 groups?
You could get out a calculator, but that's so inconvenient! Instead, apply the "vsauce Test", which can tell you whether any number is divisible by 1009 (without remainder).
Easy!
*Even though the database is complete all the way up to 30000, we do not yet cover the full list of all prime numbers. As mathematics researchers discover new cutting edge techniques for finding new primes it is possible the coming decades may see the database grow even larger!
Prime Numbered Divisors
Divisors are particularly interesting when they are prime numbers.