21
20
20 is the next number greater than 19. The next prime number greater than 19 is 23.
100,000,000,000,000,000,000 {a 1 with 20 zeros}, or 100 quintillion.
20
nothing
10
20
220
20 is the next number greater than 19. The next prime number greater than 19 is 23.
37
10
100,000,000,000,000,000,000 {a 1 with 20 zeros}, or 100 quintillion.
20
42
37
37
nothing