20 is the next number greater than 19. The next Prime number greater than 19 is 23.
19.
Ten.
43
If you mean: 9, 19, 39, 69 then the next number in the sequence is 109
23 Prime numbers are odd numbers and 21=3x7
The whole number that immediately follows 19 is 20.
31
19 is the first that comes to my mind
35
19.
Ten.
67
43
If you mean: 9, 19, 39, 69 then the next number in the sequence is 109
27
27
23 Prime numbers are odd numbers and 21=3x7