TLDR: Hawking radiation can cause things besides black holes to evaporate.

  Man and moon: 10^90 years

Because the researchers were at it anyway, they also calculated how long it takes for the moon and a human to evaporate via Hawking-like radiation. That's 10^90 years. Of course, the researchers subtly note, there are other processes that may cause humans and the moon to disappear faster than calculated.