franzi1981
Oct 14, 2011 20:11
- It's the first odd number that's not a prime
- It's a square number
- It's the first lucky number that's not a prime
- Its multiplication table is oddly soothing - the last digits go 9, 8, 7, 6, 5,...
- The digital root of numbers multiplied by 9 is... 9
mathematics,
number 9,
geekery