Obviously a hypothetical scenario. There is no way to pass on the knowledge to anyone else. Time freezes for you only, and once you have your answer you are out of this world.
The question can allow you to see into the past, present and future and gain comprehension of any topic/issue. But it's only one question.
Edit: the point isn't "how to cheat death". You can't. Your body is frozen and there is nothing you can do with this knowledge other than knowing it, and die. So if you would rather be frozen in a limbo just thinking of numbers for eternity, be my guest.
Such a variety of replies, it's been really interesting to read them!
What would you want to know? Personally I'd want to see a timelapse or milestone glimpses of humanity's future until the end of Earth's existence (if we survive that long)
If I is unknown, then he got 2 questions answered instead of 1.