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Last updated on May 26th, 2025

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Is 1981 a prime number?

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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 1981 a prime number? for Indonesian Students
Professor Greenline from BrightChamps

Is 1981 a prime number?

The number 1981 has 4 factors, that are capable of dividing the number completely without leaving any remainder. Thus, the number 1981 is a non-prime number. The factors of 1981 include 1, 7, 283, and 1981.

 

Is 1981 a prime number
 

Professor Greenline from BrightChamps

Why is 1981, 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, 1981 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
     
Professor Greenline from BrightChamps

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 1981 would simply be


Divisors of 1981= 1, 7, 283, 1981
Number of divisors= 4


The number 1981 can be considered composite.
 

Professor Greenline from BrightChamps

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 1981 are 1, 7, 283, and 1981.

 
Thus, 1981 consists of 6 factors that divide it completely without any remainder.
 

Professor Greenline from BrightChamps

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 under 100 are;
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97.


1981 is not present in the list, it is not a prime number.
 

Professor Greenline from BrightChamps

Using the Prime Factorization Method

This method is only used for a non-prime number/composite number. Since 1981 is a composite number, the prime factorization for 1981 is:


Factors of 1981 = 7 × 283
 

Max Pointing Out Common Math Mistakes

Common mistakes to avoid when determining if 1981 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.
 

Mistake 1

Red Cross Icon Indicating Mistakes to Avoid in This Math Topic

Misinterpreting all numbers to be prime.
 

Green Checkmark Icon Indicating Correct Solutions in This Math Topic

A number being odd does not decide if the number will be prime. An odd number can also be a composite number.
 

Ray Thinking Deeply About Math Problems

FAQs for "Is 1981 a prime number"

1.Is 1981 a prime number?

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2.What are the factors of 1981?

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3.What is the prime factorization of 1981?

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4.Is 1981 divisible by 2?

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5.Is 1981 divisible by 3?

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6.Is 1981 divisible by 5?

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7.Is 1981 a perfect square?

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8.Can 1981 be expressed as a product of prime numbers?

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9.How can children in Indonesia use numbers in everyday life to understand Is 1981 a prime number??

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10.What are some fun ways kids in Indonesia can practice Is 1981 a prime number? with numbers?

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11.What role do numbers and Is 1981 a prime number? play in helping children in Indonesia develop problem-solving skills?

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12.How can families in Indonesia create number-rich environments to improve Is 1981 a prime number? skills?

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Professor Greenline from BrightChamps

Important Glossary for "Is 1981 a Prime Number?"

  • Prime Number: A natural number greater than 1 that has exactly two distinct positive divisors: 1 and itself. For example, 2, 3, and 5 are prime numbers. A number like 1981, which has more than two divisors, is not prime.

 

  • Divisors: Numbers that divide a given number exactly, leaving no remainder. For 1981, the divisors are 1, 7, 283, and 1981.

 

  • Composite Number: A number that has more than two divisors. Since 1981 has six divisors, it is considered a composite number, not a prime number.

 

  • Prime Factorization: The process of breaking down a composite number into its prime factors. For 1981, the prime factorization is 7 × 283.

 

  • Divisibility Rule for 3: A rule used to determine if a number is divisible by 3. If the sum of a number's digits is divisible by 3, the number itself is divisible by 3. For example, the sum of the digits of 1981 (1 + 9 + 8 + 1 = 19) is not divisible by 3, so 1981 is not divisible by 3.
     
Professor Greenline from BrightChamps

About BrightChamps in Indonesia

At BrightChamps, we know numbers are more than just digits—it’s a way to open doors to countless opportunities! Our mission is to help kids all across the Indonesia grasp important math skills, like today’s focus on the Is 1981 a prime number?with a special focus on understanding prime numbers—in a way that’s lively, enjoyable, and easy to follow. Whether your child is figuring out how fast a roller coaster speeds through Dunia Fantasi, keeping track of scores at a local badminton game, or managing their allowance to buy the latest gadgets, mastering numbers gives them the confidence they need for everyday challenges. Our interactive lessons make learning both simple and fun. Because kids in the Indonesia learn in many different ways, we tailor our approach to fit each child’s unique style. From the bustling streets of Jakarta to the beautiful beaches of Bali, BrightChamps brings math to life, making it relatable and exciting throughout Indonesia. Let’s make prime numbers a fun part of every child’s math journey!
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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.

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Max, the Girl Character from BrightChamps

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: She loves to read number jokes and games.

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