Is 22 a Prime Number?

22 is not a prime number. But according to what we are saying, why is it not a prime number? Let's understand that, firstly, the number set is of two parts:

• Prime number

• composite numbers

And using one of the methods we're going to introduce you to, we will find that indeed 22 is not a prime.

We could find that a number is prime if it has 2 factors only, 1 and the number itself, and only 2 divisors. It means that a number, not satisfying these conditions, cannot be a prime number.

However, there are pretty simple methods to determine whether a number is prime or not:

• Count Divisor Method

• Divisibility Test

• Prime Number Table

• Prime Factorization
   

The name implies: We’re counting how many divisors a given number has, and then saying that number is prime. It is easy to learn. With that said, let’s see what steps are there in this method.

• First is to count how many the number holds in divisors.

• We can then see that 22 has more than 2 divisors: 1,2,11 and 22.

We can see that number 22 has 4 divisors. Thus, we see that it doesn’t fulfill the criteria needed for a prime number. And so it is not a prime number.
 

In this case, we'll see if 22 can be divided into any other number. Now if it gets divided then that is not a prime number. So let’s check for 2,3,5 and 7.

• Since 22 is an even number, we can say that 22 is divisible by 2.

• Since the sum of the digits is 4, 4 is not divisible by 3 as 4 is not a multiple of 3. 

• 22 is not ending with a 0 or 5. Therefore, it is not divisible by 5.

• We can use a simple trick and see if 22 is divisible by 7. We first consider the last digit, as shown 2. Double it (2 × 2 = 4), now take off that other digit 2 (2 – 2 = 0) and we get 4. So, we do 4 - 2 = 2. 2 isn’t divisible by 7 so 22 isn’t divisible by 7.

We know 22 can be divided by one of the above-mentioned numbers, therefore it is not a prime number.
 

Here, we will be using a chart that will contain all the prime numbers between 1 and 100. If the given number appears in the list, it is not a prime number. 
 

We can see that 22 does not appear here. So, it is not a prime number.
 

We use this method of breaking large numbers into small numbers, then checking the factors. It works only for composite numbers. 

The factors of 22 are 2 and 11. Since there are more than two factors for 22, we can not title 22 a prime number.
 

• Prime numbers- Any number with only 2 factors is called a prime number. The factors will be 1 and itself. For example, 2 and 3 are prime numbers because they have only 2 factors.

• Factor- A number, if multiplied with another number gives us the required number.Example, 3x2=6, 3x3=9. In that, 2 and 3 are factors.

• Co-prime Numbers- These numbers have a GCF of 1. 

• Multiple-The product we get while multiplying a number with another number. Example:- 10x2=20, 10x3=30. Here, 20 and 30 are multiples of 9.