2003

2003 is a prime number. It is a Sophie Germain prime because 2 x 2003 + 1 = 4007 is also a prime.

2003 is formed from the first two primes (2 and 3) separated by two zeroes. Add 2³, then 2 x 3 to get the next two primes: 2011 and 2017.

The concatenation of numbers from 2000 to 2003 (2000200120022003) is a prime.

2003 is the only known prime of the form 2 x 10^p + p, where p and p + 4 are primes (with p = 3).

2003 is 133103 in base 4 and 31003 in base 5.

2003 divides 22¹³ - 1.

2003 was the first prime year of the current millennium. The next two are 2011 and 2017.

Source: Number Gossip and Prime Curios!