99343...34399 (101-digits)

This number is a prime.

                                          9 9343336353 9703098727 3751779779
4909972999 6983790302 0309738969 9927990949 7797715737 2789030793 5363334399

This prime forms the bottom row in a Palindromic Prime Pyramid (of Step Size Two) which begins:

2
30203
903020309
3790302030973
98379030203097389
969837903020309738969
9996983790302030973896999
72999698379030203097389699927
997299969837903020309738969992799
9099729996983790302030973896999279909
94909972999698379030203097389699927990949