998 is the biggest 3-digit even number
1
1,999
1999
999 = 3 x 333 = 9 x 111so is a composite (not prime) number.
997 is the biggest 3 digit prime number.
998 is the biggest 3-digit even number
1
999
1,999
992
1999
The biggest nine digit number would consist fully of '9's: 999,999,999
999 = 3 x 333 = 9 x 111so is a composite (not prime) number.
The biggest 4 digit number that can be made from using the digits of 850236, using a digit at most once, is 8653.
987? It is just a guess of course.
fff. fff in hexadecimal is 4095 in decimal.