Is 997 a Prime Number?
2026-02-28 10:11 Diff
https://brightchamps.com/en-us/math/numbers/is-997-a-prime-number

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Last updated on August 5, 2025

Do you feel like checking for prime numbers can be tricky? Determining a prime number is easy. Prime numbers are used in encryption. Here, we discuss the topic called ‘Is 997 a prime number?’.

Why is 997 a Prime Number?

Since 997 has 2 factors, it is a prime number. The basic methods to check if a number is prime are the counting divisors method, divisibility method, prime number chart, and prime factorization.


 

Using the Counting Divisors Method

This method will find the total number of divisors of the given number.  If there are more than two divisors, then the given number is composite, not prime.


The divisors of 997 = 1, 997


Therefore, 997 is prime.
 

Using the Divisibility Test Method

The divisibility method determines whether a number is composite or not. Make use of the divisibility rule of 2 (if the number is even),

the divisibility rule of 3 (if the sum of digits is a multiple of 3), and so on.  Since 997 has two factors, it is only divisible by 1 and 997, the factors of 997
 

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Using Prime Number Chart

This method will check if a number is prime or not with the help of a prime number chart. Only if the number is seen in the chart, then it's a prime.
 

Prime Factorization Method

Common Mistakes to Avoid When Determining if 997 is a Prime Number

You might feel that it’s a bit tricky to check for prime numbers. There’s no need to get worried about this. Here, we will discuss the mistakes that can happen and the solutions to tackle them.
 

FAQs for ‘Is 997 a Prime Number’

1.Why is 997 not composite?

997 is not composite because it has only two factors. Only those numbers with more than two factors can be composite.
 

2.How many factors of ‘997’ are prime?

Prime numbers are natural numbers greater than 1 and have only two factors. Here, 997 is a prime number and 997 is the only prime factor.
 

3.Why is ‘1’ not prime?

Based on the definition of prime numbers, 1 cannot be a prime because all prime numbers are greater than 1.
 

4.Is 997 divisible by 3?

997 is not divisible by 3 because the sum of the digits of 997 is not a multiple of 3. Numbers whose sum of digits are multiples of 3 can be divided by 3 completely.
 

5.Is 1 a factor of 997?

Yes, 1 is a factor of 997. When 997 is divided by 1, it leaves no remainder. Therefore, we can say that 1 is a factor of 997

Important Glossaries for "Is 997 a Prime Number"

  • Prime Number: Natural number with two factors. For example, numbers like 901, 911, 2017, etc.
  • Composite Number: Numbers with more than two factors. For example, numbers like 800, 900, 100, and so on.
  • Prime Factorization: Method to express the product of prime factors using exponents.
     

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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.