Is 12 a prime number?

No, 12 is a composite number. A prime number should not have divisors more than 2 but 12 has 6 divisors.

The divisors of 12 are 1,2,3,4,6,12.  Therefore, 12 is a composite number. Composite numbers are the numbers which has factors more than 2.

A number to be a prime number it should follow the criteria which is that it should not have factors more than 2. 12 has factors more than 2 so it is a composite number.
Given below are a few ways that can be used to find prime or composite numbers.
 

In this method, the divisors of a number are listed, and the number is checked, to be called a prime number. The counting divisors method for 12 would simply be

• Divisors of 12=1,2,3,4,6,12

• Number of divisors=6

The number 12 can be considered composite.
 

In divisibility method, the prime number only has 2 divisors, which are 1 and itself.

• Divisors of 12=1,2,3,4,6,12

As 12 has factors more than 2 then it is not a prime number. 
 

We write the prime number chart up to 10, which helps in sorting numbers.

The prime numbers from 1 to 12 are 1, 2, 3, 5, 7, 11. 12 is not on the list, so it is not a prime number
 

This method is only used for a non-prime number/composite number. Since 12 is a composite number, prime factorization for 12 is :

• Factors of 12 = 2×2×3.

• Prime factors are 2 and 3.
   

• Composite Number: A number that has divisors more than 2.

• Divisibility Method: In divisibility method, the prime number only has 2 divisors, which are 1 and itself.