Question

Find the number(s) which has/have only factors as $1$ and the number itself.

• A. 2
• B. 11
• C. 4
• D. 19

Answer 1

Answer: (A), (B), (D)

19

Let's find the factors one by one.

Factors of $2:$ $1,2$
Factors of $11:$ $1,11$
Factors of $4:$ $1,2,4$
Factors of $19:$ $1,19$

$\therefore$ The numbers which have only factors as $1$ and the number itself are $2,11\&19.$