Okay, you obviously know that Near is an alias, and this little jerk's real name is Nate River. Also, according to Mikami's shinigami eyes, his lifespan reads as 43406. Which is apparently an incomplete number or some junk, but it's canon so we may as well use it. Presuming she ever manages to see his face, which of course he takes precautions against and will do even more once he's aware that Misa is about. (... At least he occasionally leaves the house now?)