47121...31191 (32-digits)

This number is a prime.

                                         47 1213643211 1521119379 3773331191

A prime such that continually deleting the outermost digits gives a prime at each step, i.e., 47121364321115211193793773331191, 712136432111521119379377333119, 1213643211152111937937733311, …, 15211193, 521119, 2111, 11. [Loungrides]