99
9999
99
99 is not a prime because it can be divisible by 3 and 33
The smallest three digit composite number is 100, and the largest two digit number is 99. 100-99=1.
The highest two-digit prime number is 97. Out of that group, the highest (and only) prime number is 71.
Highest 2-digit number = 99Highest 1-digit number = 999 - 9 = 90 two-digit numbers90.
The highest four-digit prime number is 9,973.
Lowest four-digit number: 1000 Highest four-digit number: 9999
Highest 2-digit number = 99 Highest 1-digit number = 9 Highest possible sum from 2, 2-digit numbers = 198 Highest possible sum from 2, 1-digit numbers = 18
987654321 is the highest nine-digit number with no repeated digits.
Highest number is 7
99 is. But if you want to get fancy, you might consider 99 .