1117

This number is a prime.

The smallest prime formed by concatenating the smaller members of two successive twin prime pairs: {(11, 13) ; (17, 19)}. Note that the reverse concatenation of the larger members forms an emirp (1913), and that similar properties hold for the two successive twin prime pairs {(101, 103) ; (107, 109)} : 101107 is prime while 109103 is an emirp. [Beedassy]