19. 1; 2; 3; 15; 17; 23; 28; 49; 64; 121; 304; 324; 1001 sonlari ichida nechta tub son bor?

To find the prime numbers in the given list, we need to identify which numbers are divisible only by 1 and themselves.

1. 1 is not a prime number.
2. 2 is a prime number (divisible by 1 and 2).
3. 3 is a prime number (divisible by 1 and 3).
4. 15 is divisible by 3 and 5.
5. 17 is a prime number (divisible by 1 and 17).
6. 23 is a prime number (divisible by 1 and 23).
7. 28 is divisible by 2, 4, 7, 14.
8. 49 is divisible by 7.
9. 64 is divisible by 2, 4, 8, 16, 32.
10. 121 is divisible by 11.
11. 304 is divisible by 2, 4, 8, etc.
12. 324 is divisible by 2, 3, 4, 6, 9, etc.
13. 1001 is divisible by 7, 11, 13.

The prime numbers in the list are 2, 3, 17, and 23.

Ответ: 4