20.4583
0.0489
1, 7, 491, 2, 5, 10, 25, 50
49 divided by 7 =7
1
7
491-216 = 275
5's the obvious one, so we factor 5 out and get 1473. No more fives left, obviously, but 1473 follows the rule of factoring by 3 (1+4+7+3=15, which is divisible by three), so we factor 3 out and get 491. 491 isn't divisible by three 3, so we find the nearest square to 491, which is 484 (22*22). We test all the remaining prime numbers 22 or less: 7, 11, 13, 17, 19. None work, meaning 491 is prime. So the factors of 7365 are 3, 5, and 491.
the answer is 7
1-492 = -491
Yes. 491 is prime.
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