What Kind of Number is 2?
This is one of the most common questions asked by the students learning prime and composite numbers.
Since 2 is an even number it is a bit difficult to accept and understand if 2 is prime or not.
2 is a special number which doesn't seem to be prime as it is even and is divisible by 2 but it is a prime number.
2 is a Prime Number or Not?
Yes, 2 is a prime number. We can justify this by the definition of prime numbers. A prime number is a number which has only two factors that is 'one' and the number itself. This can be put into simple words as - a prime number is only divisible by 'one' and itself. So, when a question is put up, why is 2 a prime number or how is 2 a prime number, we can justify ourselves by saying that since 2 has only two factors or it is divisible only by 'one' and itself, hence it is a prime number.
Is 2 a Composite Number?
Composite numbers are opposites of prime numbers. These are those numbers that have more than two factors. They are divisible by 'one' and themselves but also by at least one more number. So when someone says 2 is a composite number we can deny it by saying, since there is no other number than 'one' and 2 itself which can divide 2 hence it is not a composite number.
Which is the Only Even Prime Number?
Numbers are also categorized as even and odd numbers. Even numbers are those which are divisible by 2 and odd ones are not divisible by 2.
For a number to be both even and prime together, it needs to be divisible by 2 but at the same time it should not have more than two factors that are the other number with which it is divisible has to be 'one'.2 is an even number and the only other factor it has is 'one'.So using these facts, we can definitely say that 2 is an even prime number. Why is 2 the only even prime number or is 2 the only even prime number? We can answer this in positive because there is no other number that fulfils the necessary conditions to be both even and prime at the same time. So yes,2 is the only even prime number.
What Kind of Number is 2
As stated above, 2 is a special number that fulfils many requirements and can be put under different categories or classifications of numbers.
Following ate the categories where 2 finds its place
A natural number
A whole number
A positive integer
A rational number
A prime number
An even number
2 is the smallest prime number
2 is the smallest even number
2 is the only even prime number
Is 2 the Only Prime?
The answer to this question is no. There are many such numbers that fulfil the necessities to become a prime number that is they are divisible only by themselves and 'one'.The other prime numbers are 1,3,5,7,11,13…..and so on.
Some Important Points about Prime Numbers
Other than 2 rest all prime numbers are odd numbers and only 2 is the even prime number.
The only two consecutive prime numbers are '2' and '3'.
6n+1 or 6n-1 is the form in which all prime numbers can be represented except '2' and '3', where n is the natural number.
All even numbers greater than 2 can be represented as the sum of two prime numbers.
There are 24,862,048 digits in the largest prime number found.
There is an organization dedicated to finding the largest prime numbers.
Prime numbers protect us from cybercrime.
The Sieve of Eratosthenes was the earliest method of finding prime numbers.
Zero and 1 are not considered prime numbers.
Prime numbers that are two spaces apart are called twin primes.
Prime numbers are infinite.
There is no prime number greater than 5 that ends in a 5.
When two prime numbers are multiplied the result is called semiprime.
1. Can an Even Number be a Prime Number?
For any number to be a prime number it should have exactly two factors that are the number itself and 'one'.But an even number has at least three factors that are the number itself, 'one' and two.
So, generally, an even number cannot be a prime number. However, there is an exception to this as '2' is an even number and also it is a prime number. The reason for this is the number '2' in spite of being an even number has only two factors that is 'one' and 2 itself. In fact, it is the smallest prime number and the only even prime number. So except 2 an even number cannot be a prime number.
2. Why is 1 not a Prime Number?
1 is not a prime number because it does not satisfy the definition of prime number that is it has 1 as the only factor to it whereas prime numbers have exactly two factors. The number one is far more special than a prime number. It is neither prime nor composite. Every number is divisible by 1.It is the unit (the building block) of the positive integers, hence the only integer which merits its own existence axiom in Peano's axioms. ... for all positive integers n 1 is the only perfect nth power. It has exactly one positive divisor and is the only positive integer to have such property.