I also found a pile of possibilities, and thought that those ten letters might help -- I considered DR WATSON to match the eight digits, but if a simple substitution cipher the "7" on each end should be the same letter. Also, I was not sure whether "unlike YOU!" could/should be regarded as saying YOU was a prime.
As the propounder says (another clue??) "WHERE ARE WE?" Since someone decided to categorize this under "RIDDLES" perhaps this is not even a decoding puzzle at all. If it is genuine, I would think that question points to the decoded number as a physical location, though his title suggests a sobriquet (e.g "my dear fellow" or the like). Perhaps the ravenous "Nevermore"...
Riddle Me This
