* 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)