The magic constant for the smallest magic square composed only of prime numbers if 1 were counted as a prime.
111322 + 322111 is prime. [Kulsha]
The number of consecutive composites that follow the prime 370261, the first run of more than 100.
Nayan Hajratwala's home computer, a 350 MHz IBM Aptiva, used 111 days of idle time to find the thirty-eighth Mersenne prime.
111 equals the sum of 2 + 3 + 4 + ... + 17 minus the sum of primes less than 17. [Trotter]
111*10^100+1 is the smallest prime which is one more than a multiple of googol. [Wu]
The smallest multi-digit palindromic number n such that the number of primes below n^2 does not exceed n times the number of primes below n. [Russo]
111 x 2111 - 111 - 2111 is prime. [Noll]
(There are 8 curios for this number that have not yet been approved by an editor.)