Identify whether the given number is a prime number.

$331$

Identify whether the given number is a prime number.

$167$

Identify whether the given number is a prime number.

$203$

Identify whether the given number is a prime number.

$161$

Write the common factors of the following numbers :

$20,28,32$.

Write the common factors of following numbers :

$15,25,30$

Write the common factors of following numbers :

$75,60,210$

Write the common factors of following numbers :

$42,63,105$

Write the common factors of following numbers .

$12,18,24$