All natural numbers are either prime or composite numbers.

The product of two prime numbers is a prime number.

Using the divisibility rule, divide the given number by $3$ and check if it is divisible by $3$ or not.

$47$

Using the divisibility rule, divide the given number by $3$ and check if it is divisible by $3$ or not.

$53$

Using the divisibility rule, divide the given number by $3$ and check if it is divisible by $3$ or not.

$139$