99999...81919 (100-digits)

This number is a prime.

                                            9999999999 9999999999 9999999999
9999999999 9999999999 9999999999 9999999999 9999999999 9999999999 9999981919

Just showing those entries submitted by 'Bajpai': (Click here to show all)

The largest emirp less than a googol using invertible digits only. [Bajpai]