what is a prime number ? is 1 a prime number ?

Which number is not a prime number nor a composite number ?

what is prime number.give few examples

What is the smallest prime number?

The numbers 17 and 71 are prime numbers. Both these numbers have same digits 1 and 7. Find 2 more such pairs of prime numbers below 100?

Find the probability that a number selected from the numbers 1 to 25 is not a prime number when each of the given numbers is equally likely to be selected.