900
It is the only three digit number with a nine in the numbers place
The largest 5 digit number would obviously have to be 99,999. That's ninety-nine thousand, nine hundred and ninety-nine.
The largest 9 digit number is 999,999,999 (nine hundred and ninety nine million, nine hundred and ninety nine thousand, nine hundred and ninety nine).
The largest eight-digit prime number is 99,999,991. The smallest nine-digit number, for comparison, is 100,000,019.
999999999
999.
9 (nine)
9,999 (nine thousand, nine hundred ninety-nine).
36
999,950,884 = (31,622)2
9,999th or nine thousand nine hundred and ninety ninth
144
108