1979 is a prime number because it has only two factors, i.e. 1 and 1979.

985 is not a prime number because it has more than two factors.

There are 3 prime numbers (71, 73, 79) between 70 and 80. 

987 is not a prime number because it has more than two factors.

883, 907 and 919 all are prime numbers.

There are 5 prime numbers (127, 131, 137, 139, 149) between 120 and 150.

There are 15 prime numbers from 1 to 50.

There are 5 prime numbers (601, 607, 613, 617, 619) between 600 and 620. 

97 is a prime number.

There is only 1 prime number from 90 to 100.

21 is not a prime number.

There are 12 prime numbers from 25 to 75.

43 is the 14^th prime number.

1433 is prime number because it has only two factors, i.e. 1 and 1433 (number itself).

41 is a prime number because it has only two factors, i.e. 1 and 41 (number itself).

Prime numbers starting from the smallest are: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53 So, 53 is the 16^th prime number.

Prime numbers between 1 and 100 are: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97 So, there are 25 prime numbers between 1 and 100.

3 has only 2 factors, i.e. 1 and 3. So, 3 is a prime number.

23 is a prime number because it has only two factors, i.e. 1 and 23 (number itself).

There are 6 prime numbers between 210 and 240. These are 211, 223, 227, 229, 233 and 239.

1 is not a prime number.

39 is not a prime number.

89 is a prime number.

There are 4 prime numbers between 50 and 70.