719

719 is:

a prime number 

a factorial prime (6! − 1) = a prime number that is some number factorial plus or minus 1

a Sophie Germain prime = a prime, p, such that 2p+1 is also prime

a safe prime = the inverse of a Sophie Germain prime

the sum of seven consecutive primes (89 + 97 + 101 + 103 + 107 + 109 + 113)

a Chen prime = a prime number where the number 2 more than it is either a prime or a pq number

an Eisenstein prime with no imaginary part = I can't figure out what the hell that is.

 - (from my Facebook friend Kevin L. Schwartz, who posted this when his page had 719 "like"s.  He got it from Wikipedia.)