A.) It was clearly a joke.
B.) That number was based off the Wikipedia heat death of the universe page reference for this: https://arxiv.org/abs/hep-th/0410270
C.) Regardless of the correct amount of time, no one will be there to verify it. We don't even understand enough yet to say with absolute confidence that heat death is the definitive final outcome of the universe.
According to Don Page[1], that time (for our universe) is approximately 10^10^10^10^2.08 "Plank times, millenia, or whatever"[2].
[1] http://arxiv.org/abs/hep-th/9411193
[2] The units given in the paper (see [1], page 8)
Numberphile video about this paper: https://www.youtube.com/watch?v=1GCf29FPM4k