The number whose only factors are 1 and the number itself is called a/an _________ number.

The number of prime numbers lying between 323 and 332 is:

The number of prime numbers having two digits in which the digits are also prime is

The number of prime numbers lying between 393 and 401, both included, is:

The number of prime numbers lying between 466 and 476, both included, is:

The number of prime numbers lying between 430 and 438, both included, is:

The number of prime numbers lying between 400 and 430 is:

Which one of the following numbers is NOT a prime number?

The number of pairs of twin primes between 1 and 100 are:

How many prime numbers are there that are less than 50?

Which of the following numbers is NOT a prime number?