This number is a composite.
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 multidigit 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]
The smallest nontrivial palindromic semiprime. [Silva]
111 is the total number of prime numbers that can be displayed on a 12-hour digital clock. [Ward]
The sum of the emirp pair 37 and 73 plus 1 is a repunit, i.e., 37 + 73 + 1 = 111. Additionally, the sum of n of these emirp pairs plus n is also a repdigit, for n = 2 thru 9. [Wiszowaty]