Multiple choice general knowledge math & puzzles Which one of the following is a Prime number? 33 81 93 97 Reveal answer Fill a bubble to check yourself D Correct answer Explanation 97 is a prime number as it has no divisors other than 1 and 97. 33 is divisible by 3 and 11; 81 is divisible by 3 and 9; 93 is divisible by 3 and 31. Thus, 97 is the only prime in the list.