The "Odd" One Out

$2$ is the smallest prime number as $2=2×1$ which has 2 common factors

(why not 1) as $1=1×1$ which has only one factor $1$ so its not a prime

(why not 3) as $3$ is also a prime number but greater than $2$ so its not the correct choice

Some people will choose the answer $1$ at first glance.. But the reality is the number $1$ has just only $1$ divisor.. $1= 1*1$ , So, $1$ is neither prime nor composite.. But the number $2$ has 2 divisors, $(2=2*1$ ), which is the main characteristic of a prime number. Thus, $2$ is the $\color{#E81990}\boxed{\text{Smallest Prime Number}}$ in the world being an even!

All numbers that $a$ must be a factor of zero.(It means that $a | 0$ ).

One only has one factor, 1, so 1 is not prime.

Two has only 2 factors, and so it is the smallest prime.

3 has 2 factors, but it is not the smallest, so it cannot be answered.