Is -7 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 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:

• 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 -7 is not a positive number greater than 1, it is not a prime number.

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.

• Prime numbers: Positive integers greater than 1 with no divisors other than 1 and itself.
   
• Composite numbers: Natural numbers greater than 1 that are divisible by more than 2 numbers.
   
• Divisibility tests: Methods to determine if a number is divisible by another without leaving a remainder.
   
• Absolute value: The non-negative value of a number without regard to its sign.
   
• Natural numbers: Positive integers starting from 1 and increasing without end.