Mouth of Sauron: Secrets

[Kuruharan]

could it be possible he could be one of the original numenorians in the survace of sauron at the time of ar-pharazon?

That would put him right up there with the Nazgul, and I really rather doubt that. No doubt that he was quite old, but not that old. In fact the text says...

And he entered the service of the Dark Tower when it first rose again, and because of his cunning he grew ever higher in the Lord's favor...

The reconstruction of Barad-dur began in 2951, although he may have entered Sauron's service a little before that date. That is a relatively brief time to have been in Sauron's pay. He must have had a rather long career elsewhere in the world before he took up the job as Lieutenant of the Tower. Or maybe he is just not as old as he is usually credited as being.

And before anyone says something to the effect of, "Well, then obviously he had served Sauron from before the time of the Last Alliance," he clearly did not. Barad-dur was destroyed by the Last Alliance. The phrase "when it first rose again" shows that he joined Sauron when he returned to Mordor, after the events in The Hobbit.