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Last updated on April 28th, 2025
The numbers that have only two factors, which are 1 and itself, are called prime numbers. Prime numbers are used in encryption, computer algorithms, and barcode generation. In this topic, we will be discussing whether -7 is a prime number or not.
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 greater than 1 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:
The characteristic of a prime number is that it has only two divisors:
1 and itself, and is greater than 1.
Since -7 is a negative number, it does not meet the criteria for being a prime number.
A few methods are used to distinguish between prime and composite numbers, but the primary criterion is that the number must be a positive integer greater than 1.
The method of counting divisors to categorize numbers as prime or composite applies only to positive integers.
Negative numbers do not fit the definition of prime numbers.
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.
However, since -7 is negative, it does not qualify for this method.
Divisibility tests are used to determine whether a number is divisible by another number without leaving a remainder.
However, these tests are only applicable to positive integers when determining primality.
Since -7 is negative, it does not qualify for these tests to determine if it is a prime number.
A prime number chart is a tool used to identify prime numbers within a range of positive integers. The Sieve of Eratosthenes, for example, is a common method for generating a list of prime numbers.
Step 1: Write numbers from 1 to 100 in 10 rows and 10 columns.
Step 2: Leave 1 without marking, as it is neither prime nor composite.
Step 3: Mark prime numbers and cross out their multiples.
Since -7 is not a positive integer, it is not included in the prime number chart.
Prime factorization involves breaking down a positive integer into its prime factors. This process is not applicable to negative numbers, such as -7, as they do not meet the criteria for prime numbers.
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.
: She loves to read number jokes and games.