The number of days between the previous terrorist attack on the Twin Towers and 9/11. Note the appearance of 911 in the reversal of 3119.
The smallest prime factor of the 43-digit number of terms
required to obtain a sum of 100 in the harmonic series.
The only non-titanic prime of form n^n-6, where n is an integer, (case n=5) [Loungrides]
The smallest right-truncatable prime concatenated from two double-digit primes. [Loungrides]