Is 89 a Prime Number?

There are many types of numbers, like prime numbers and composite numbers. 89 is a prime number. We can get a prime number using a number of techniques. Now, let us understand what are those techniques.
 

A number can be prime only if it meets these 2 criteria:

• It should be a number greater than 1 and a whole number.
• It should have only 2 divisors. (1 and itself)

The number is prime if both of the above conditions are met. There are some ways by which a prime number can be determined. Some of them are mentioned below.

1. Counting Divisor Method
2. Divisibility Test
3. Prime Number Chart
4. Prime Factorization

Let's consider these methods and see why 89 is a prime number.
 

Here we would see how many divisors 89 carries. If it has 2 divisors, it is a prime number.

• Let us write down how many divisors 89 has.

• Number of divisors for 89–1 and 89

We can clearly see that 89 has only 2 divisors. So we can say that 89 is a prime number.
 

Here we are going to see whether 89 is divisible by some other number or not. Let's check for 2, 3, 5, and 7.

• Only if the last digit is even, it is a multiple of 2. Number 9 is not a multiple of 2. Then 89 can not be a multiple of 2.

• A number is a multiple of 3 if the sum of the digits is a multiple of 3.

For example, 36. The sum of 3+6=9. Now, that is a multiple of 3. So, 36 is a multiple of 3. Now, look at the case with 89, the sum of 8 and 9 is 17 (8+9=17). Number 17 is not a multiple of 3 and so 89 is not divisible by 3.

• A number is divisible by 5 if it is either with a 0 or 5. But 89 ends with a 9. Due to this, 89 is never divisible by 5.

• The above number 89 has to be a multiple of 7 for being divisible by 7. So, the last digit 9 has to be doubled and that will give us 9×2=18 and that should be subtracted with the other digit 8. Then we get the result of 10. 18-8=10. This is not a multiple of 7. So 89 cannot be divided.
   

This is the easiest way of finding a prime number. We would have a list of all the prime numbers, and we can check if the number given is a prime number. Let's see the prime numbers from 1 to 100.

The table has the number 89. We know it is a prime number.
 

Here we break the big numbers into small prime numbers to confirm the number of factors they have. But it is not used for prime numbers.
 

• Composite number- A number which has more than 1 factor is called a composite number.
•  

For example, — 18 is factorized into 2×32, hence it is a composite number.

• Multiple-The product we get while multiplying a number with other numbers.

Example:- 9×2=18, 9×3=27. Here, 18 and 27 are a multiple of 9.

• Factor-A number, if multiplied with other number, gives us the required number.

Example, 9×2=18, 9×3=27. In that, 2 and 3 are factors

• Square of a number-The product we get while a number is multiplied by itself.

For example, 2 ² = 4; 3 ³ = 9; 4 × 4 = 16. That may be represented as 2², 3², 4².