443

443 is a prime number. It is the 24th Sophie Germain prime: 443 x 2 + 1 = 887, which is also prime.

443 is the first three-digit non-palindromic prime number whose binary equivalent (110111011) is a palindromic prime in base 10.

The sum of the digits of 443 is a prime: 4 + 4 + 3 = 11. Hence, 443 is an additive prime

443 is the smallest prime containing exactly two 4s.

Telephone area code 443 includes Baltimore, Md.

Source: Prime Curios!