111191111

This number is a prime.

                              31111911113
                             3311119111133
                            333111191111333
                             9911119111199
                              91111911119

Each of the above five palindromic numbers is prime. 111191111 is the smallest palindromic prime with this property. [Firoozbakht]

(There are 2 curios for this number that have not yet been approved by an editor.)