Because they are the first five numbers divisible only by one and themselves.
The first five prime numbers before 28 are 23, 19, 17, 13, and 11.
i know what 2 prime numbers are. you want to know? do you really want to know. well, heres the answer. i don't know what 2 prime numbers are but i do know what 2 prime numbers are. sorry. hahaha. :)
It is hard to for historians to know exactly who "discovered" prime numbers. It is believed that the ancient Egyptians had some knowledge about prime numbers. However it was the ancient Greeks who get most of the credit for being the "first" to study prime numbers.
You can do prime factorization with probably every numbers. You have to be specific about the numbers you want to know.
Numbers that have more than two factors are not prime numbers because prime numbers have only two factors.
The way to know the Prime Numbers is to find out if they can only Multiplied Once ,The way to know Composite Numbers is to find out if they can be Multiplied Twice
It is impossible to know the number of prime numbers because there is an infinite number of them.
2 and 3 Prime numbers have only two factors.
Here's one. It is the first number divisible by the first three prime numbers.
Prime numbers only have two factors.
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They are relatively prime.