117 LearnersLast updated on May 26th, 2025
Is 791 a Prime Number?
The numbers that have only two factors, which are 1 and itself, are called prime numbers. For encryption, computer algorithms, and barcode generation, prime numbers are used. In this topic, we will be discussing whether 791 is a prime number or not.
Is 791 a Prime Number?
There are two types of numbers, mostly — prime numbers and composite numbers, depending on the number of factors. A prime number is a natural number that is divisible only by 1 and itself. For example, 3 is a prime number because it is divisible by 1 and itself. A composite number is a positive number that is divisible by more than two numbers. For example, 6 is divisible by 1, 2, 3, and 6, making it a composite number. Prime numbers follow a few properties like: - Prime numbers are positive numbers always greater than 1. - 2 is the only even prime number. - They have only two factors: 1 and the number itself. - Any two distinct prime numbers are co-prime numbers because they have only one common factor, which is 1. Since 791 has more than two factors, it is not a prime number.
Why is 791 Not a Prime Number?
The characteristic of a prime number is that it has only two divisors: 1 and itself. Since 791 has more than two factors, it is not a prime number. A few methods are used to distinguish between prime and composite numbers. These methods include: - Counting Divisors Method - Divisibility Test - Prime Number Chart - Prime Factorization
Using the Counting Divisors Method
The method in which we count the number of divisors to categorize the numbers as prime or composite is called the counting divisors method. Based on the count of the divisors, we categorize numbers as prime or composite. - If there is a total count of only 2 divisors, then the number would be prime. - If the count is more than 2, then the number is composite. Let’s check whether 791 is prime or composite. Step 1: All numbers are divisible by 1 and itself. Step 2: Divide 791 by 2. It is not divisible by 2, so 2 is not a factor of 791. Step 3: Divide 791 by 3. It is not divisible by 3, so 3 is not a factor of 791. Step 4: We can simplify checking divisors up to the square root of 791, approximately 28. Step 5: When we divide 791 by 7, it is divisible, making 7 a factor of 791. Since 791 has more than 2 divisors, it is a composite number.
Using the Divisibility Test Method
We use a set of rules to check whether a number is divisible by another number completely or not. It is called the Divisibility Test Method. - Divisibility by 2: 791 is odd, so it is not divisible by 2. - Divisibility by 3: The sum of the digits in 791 is 17. Since 17 is not divisible by 3, neither is 791. - Divisibility by 5: The unit’s place digit is 1, so 791 is not divisible by 5. - Divisibility by 7: When dividing 791 by 7, it results in a whole number, so 791 is divisible by 7. - Divisibility by 11: The alternating sum of the digits of 791 is 9 - 1 + 7 = 15, which is not divisible by 11. Since 791 is divisible by 7, it has more than two factors, making it a composite number.
Using Prime Number Chart
The prime number chart is a tool created by using a method called “The Sieve of Eratosthenes.” In this method, we follow the following steps: Step 1: Write numbers from 1 to 1000 in rows and columns. Step 2: Leave 1 without coloring or crossing, as it is neither prime nor composite. Step 3: Mark 2 because it is a prime number and cross out all the multiples of 2. Step 4: Mark 3 because it is a prime number and cross out all the multiples of 3. Step 5: Repeat this process until you reach the table consisting of marked and crossed boxes, except 1. Through this process, we will have a list of prime numbers. Since 791 is not present in this list, it is a composite number.
Using the Prime Factorization Method
Prime factorization is a process of breaking down a number into its prime factors. Then multiply those factors to obtain the original number. Step 1: We can write 791 as 7 × 113. Step 2: Both 7 and 113 are prime numbers. Hence, the prime factorization of 791 is 7 × 113, confirming it is not a prime number.
Common Mistakes to Avoid When Determining if 791 is Not a Prime Number
Children might have some misconceptions about prime numbers when they are learning about them. Here are some mistakes that might be made by children.
Mistake 1
Assuming That All Odd Numbers Are Prime
Solution: Children often assume that all odd numbers are prime numbers. They should be taught that except for 2, most prime numbers are odd, but not all odd numbers are prime. For example, 15 is an odd number, but it has more than two factors, which makes it a composite number.
Mistake 2
Confusing 1 as a Prime Number
Children should know the definition of a prime number as having only two factors. But 1 has only one factor, which is itself. 1 is a unique number that is neither a prime nor a composite number.
Mistake 3
Depending Too Much on Memorization
Children rely on memorizing the prime numbers. But they might forget whether 29 or 39 is prime. To avoid these kinds of problems, children should have knowledge of divisibility rules rather than depending on memorization.
Mistake 4
Applying Divisibility Rules Incorrectly
When children divide a number by another number, they might make mistakes in calculation. For example, children might make mistakes while dividing 72 by 3. Teach them shortcuts, like if the sum of the digits of a number is divisible by 3, then the number is also divisible by 3.
Mistake 5
Assuming That Negative Numbers Are Prime
Children might think that negative numbers can also be prime numbers. For example, they might apply the divisibility rule of 2 for -48 to check whether it is prime or not. They need to know that prime numbers are positive numbers greater than 1.
FAQ on is 791 a Prime Number?
1.Is 791 a perfect square?
2.What is the sum of the divisors of 791?
3.What are the factors of 791?
4.What are the closest prime numbers to 791?
5.What is the prime factorization of 791?
6.How can children in Indonesia use numbers in everyday life to understand Is 791 a Prime Number??
7.What are some fun ways kids in Indonesia can practice Is 791 a Prime Number? with numbers?
8.What role do numbers and Is 791 a Prime Number? play in helping children in Indonesia develop problem-solving skills?
9.How can families in Indonesia create number-rich environments to improve Is 791 a Prime Number? skills?
Important Glossaries for "Is 791 a Prime Number"
Composite numbers: Natural numbers greater than 1 that are divisible by more than 2 numbers are called composite numbers. For example, 12 is a composite number because 12 is divisible by 1, 2, 3, 4, 6, and 12. Factors: The numbers that divide the number exactly without leaving a remainder are called factors. For example, the factors of 4 are 1, 2, and 4 because they divide 4 completely. Divisibility rules: Guidelines that help determine if one number is divisible by another without performing division. Prime factorization: The process of expressing a number as the product of its prime factors. Sieve of Eratosthenes: An ancient algorithm used to find all prime numbers up to a specified integer.
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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
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