The list of prime numbers from 1 to 100 is also follows:

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, and 97.

Therefore, we can say that the prime numbers between 12 and 20 are 13, 17, and 19. 

19 is the greatest among all.