0.5164541789407885653...

This number is neither prime nor composite.

                                   0.516454 1789407885 6533048734 2971522858
8159685534 1541970144 1931065273 5687014402 1272349915 4883293666 2153740324

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

The sum of reciprocals of Mersenne primes. [Gudipati]