* The first non-prime odd number.
- The square of 3.
- The square root of 81.
- In the expression "on cloud nine", a symbol for elation and well-being.
- The winner in the "sans serif lower-case g look-alike digit contest"
- 1001
- the second positive digit that is invalid as an octal number...
- For any prime p, not equal to 2 or 5, there are infinitely many numbers consisting only of 9's that are divisible by p. For instance:
99 / 11 = 9
999999 / 7 = 142857
(Any one familiar with number theory should know this - just think Fermat :-)- Defined value for Pi (Indiana only)