Find:

Two perfect numbers less than $50$.

_____ is the smallest odd prime number.

Fill in the blanks:

_____ is the smallest composite number.

_____ is the greatest prime number less than $20$.

The number $2$ is the only _____ number that is even.

The number of prime numbers less than $100$ is _____.

_____ is the smallest odd composite number.

The numbers $69$ and $71$ are twin primes.