11010...10001 (39-digits)

This number is a prime.

                                  110100000 0101011111 1000101001 1001110001

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

110100000010101111110001010011001110001 is believed to be the smallest number that is prime in every base 2 through 10. [Dobb]