108

This number is a composite.

+ 108 = 22 * 33 (the product of the first two primes raised to themselves). [Sladcik]

+ The difference between the smallest (136) and second smallest (244) sums of squares (a^2 + b^2) where both a and b have more than one prime factor. [Hunter]

+ The concatenation of 108 with its previous and next number is prime, i.e., 108107 and 108109 are primes. [Bopardikar]

+ The smallest possible sum for a set of six distinct primes such that the sum of any five is prime: {5, 7, 11, 19, 29, 37}. [Honaker , Noe , Porter]

+ The sum of first 108 primes is prime. [Bajpai]

+ The concatenation of the first 108 positive integers that are squares or higher powers is a prime number. [Gaydos]

+ The first 108 digits in the decimal expansion of e form a semiprime. [Irvine , Wilson , Mishima]

+ A number in a Galois field can have any, fixed precision one desires! It does not have to be 1, 0, or even 8. [Gerck]

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