Multiple choice general knowledge math & puzzles 9,25,49,121,169,289,361,? 587 441 625 529 789 Reveal answer Fill a bubble to check yourself D Correct answer Explanation The numbers are squares of primes: 3, 5, 7, 11, 13, 17, 19. The next prime number is 23, and its square is 529. 441 is 21 squared (not prime) and 625 is 25 squared (not prime).