What a prime number is
We have to be careful by what we mean by a
concerned only with positive whole numbers that are prime. Hence a
prime number, or just a "prime", is a positive whole number that is
1 and which when it divides a product of two numbers divides at least
one of those two numbers. Consequently, a prime number is only
divisible by itself and 1; It has no proper factors.
Although 1 is a positive whole number only divisible by itself
1, it is treated separately because any number can be forever repeatedly divided by 1.
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