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# Why is 2 the only even prime number?

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Two is the only even prime number because other even numbers have at least three or more positive divisors. A number can only be considered prime when it only has two positive divisors: itself and 1.

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Even numbers that are higher than 2 are composite numbers, because they have already themselves, 2 and 1 as definite divisors. There is an infinite number of primes, all of which (except the number 2) are odd numbers. A simple way to determine the primality of a number is through trial division, which is done by dividing the number starting with the divisor 2 and up to the number's square root. If any of the quotients doesn't have a remainder, then the number is not a prime number.

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## Related Questions

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The number 111 is not a prime number. For a number to be considered a prime number, it cannot be divided by more than just itself and the number one. The number 111 is divisible by three and 37.

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The number 87 is not a prime number. The factors of 87 are 1, 3 and 29. A prime number must have only two factors, the numbers one and the number itself.

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83 is a prime number. A prime number is a number that is only divisible by itself and the number 1, without producing a remainder.

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Seven is a prime number. A prime number is a positive number that only has two possible divisible numbers. A prime number can only be divided by one and itself. The number 7 can only be divided by 1 or 7, and no other number equally divides it.