Is 1989 a prime number?
2026-02-28 23:37 Diff
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Last updated on January 16, 2026

Prime numbers have only 1 and the number itself, as factors. They are used in digital security and in securing digital payments. The topics below will help you gain more knowledge on the prime numbers and how they are getting categorized.

Is 1989 a prime number?

The number 1989 has got 6 factors, that are capable of dividing the number completely without leaving any remainder. Thus, the number 1989 is a non-prime number. The factors of 1989 include 1, 3, 9, 13, 17, 39, 51, 117, 153, 221, 663, and 1989.

Why is 1989 not a prime number?

A number to be a prime number should follow the criteria, which is that it should not have factors more than 2. Here, 1989 has more than 2 factors, hence making it a composite number. Given below are a few ways that can be used to find prime or composite numbers.


The different methods we can use to check if a number is a prime number are explained below:

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

Using the Counting Divisors Method

For the counting divisors method, it is to be checked whether the number is divisible by any numbers other than 1 and the number itself.


The counting divisors method for 1989 would simply be:


Divisors of 1989 = 1, 3, 9, 13, 17, 39, 51, 117, 153, 221, 663, 1989
Number of divisors = 12


The number 1989 can be considered composite.

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Using the Divisibility Test Method

In the division test, we try to divide the number by any of the prime numbers. If we cannot, then it is considered a prime number.


In the divisibility method, the prime number only has 2 divisors, which are 1 and itself.
The divisors of 1989 are 1, 3, 9, 13, 17, 39, 51, 117, 153, 221, 663, 1989.


Thus, 1989 consists of 6 factors that divide it completely without any remainder.
 

Using the Prime Number Chart

The prime number chart is the list of prime numbers starting from 2 to infinity.


The list of prime numbers from 1900 to 2000 are:
1901, 1907, 1913, 1931, 1933, 1949, 1951, 1973, 1979, 1987, 1993, 1997, 1999


1989 is not present in the list, so it is not a prime number.
 

Using the Prime Factorization Method

This method is only used for a non-prime number/composite number. Since 1989 is a composite number, the prime factorization for 1989 is:


Factors of 1989 = 3 × 3 × 13 × 17
 

Common mistakes to avoid when determining if 1989 is a prime number

It is highly likely we commit some mistakes due to confusion or unclear understanding. Let us look at possible mistakes we may make and try to avoid them.
 

FAQs for “Is 1989 a prime number”

1.Is 1989 a prime number?

No, 1989 is not a prime number because it has divisors other than 1 and itself.
 

2.What is the largest prime factor of 1989?

The largest prime factor of 1989 is 17.
 

3.What is the smallest prime factor of 1989?

The smallest prime factor of 1989 is 3.
 

4.Is 1989 a composite number?

Yes, 1989 is a composite number because it has divisors other than 1 and itself.

5.How to express 1989 as a product of prime factors?

6.Do any perfect squares exist in the prime factors of 1989?

7.Do any perfect cubes exist in the prime factors of 1989?

8.What can 1989 be divided by?

1989 can be divided by 1, 3, 9, 13, 17, 39, 51, 117, 153, 221, 663, and 1989.
 

Important Glossary for "Is 1989 a Prime Number?"

  • Prime Number: A natural number greater than 1 that has only two divisors: 1 and itself. Prime numbers are important in various fields like cryptography and digital security. Example: 2, 3, 5, 7.
  • Composite Number: A natural number greater than 1 that has more than two divisors, meaning it can be divided by numbers other than 1 and itself. Example: 4, 6, 1989.
  • Divisibility Test: A method to check if a number is divisible by another number without leaving a remainder. It helps determine whether a number is prime or composite by checking if it can be divided evenly by smaller numbers.
  • Prime Factorization: The process of breaking down a number into its prime factors. For example, the prime factorization of 1989 is 3 × 3 × 13 × 17.
  • Divisors: The numbers that divide evenly into a given number. For example, the divisors of 1989 are 1, 3, 9, 13, 17, 39, 51, 117, 153, 221, 663, and 1989.

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Hiralee Lalitkumar Makwana

About the Author

Hiralee Lalitkumar Makwana has almost two years of teaching experience. She is a number ninja as she loves numbers. Her interest in numbers can be seen in the way she cracks math puzzles and hidden patterns.

Fun Fact

: She loves to read number jokes and games.