9876543
98765
987653
odd
975
99
9876543.
987654
9876543
98765
987653
137?
odd
975
999 is the greatest 3 digit number and it is odd because it ends with a 9.
The answer is 1. The smallest prime is 2 and the greatest prime (of however many digits) must be odd. The remainder of ANY odd number when divided by 2 must be 1.
3201