47867...11079 (26-digits)

This number is a prime.

                                                478677 4223206688 0047611079

F. Cohen and J. L. Selfridge [CS1975] observed that the above prime number plus or minus a power of 2 can never be a prime power.

Zhi-Wei Sun [Sun2000] extended the work of Cohen and Selfridge slightly to show that none of the numbers 47867742232066880047611079 + 66483084961588510124010691590k can be written as a sum or difference of two prime powers. [Caldwell]