Abraham de Moivre was a very famous mathematician in France who is still studied and talked about today for his Moivre formula. But he is most famous for his work in normal distribution and in probability theory, simple to put because he was able to apply his theory to his own life & predict his own death.
One of his fascinations was studying mortality and putting together tables with his findings. He actually is the mathematician credited with spending the most time trying to connect death with numbers. As a result, he put together theory and a formula which could predict a day a person was going to die.
It all started when he started to age and notice that his sleep duration was shifting, Moivre discovered that he had begun to sleep 15 more minutes than normal. And this was increasing, every night he was sleeping a little longer. Putting the math together was trivial for a mathematician of his stature, and he quickly figured out that on November 27th, 1754 his sleep time would add up to 24 hours.
This was what Moivre believed was the way to pinpoint when you would die, his theory outlined that if you were sleeping 24 hours at 80 plus years old then it surely meant you would never wake up. And guess what? Abraham de Moivre died on November 27, 1754.
Though it may just have been stubbornness, and a desire to be right. Maybe he just wanted the annals of time to keep him listed as an amazing statistician. When the day did come he did indeed die, but he just stayed in bed forcing himself to sleep the 24 hours. In fact, the official cause of his death was indeed sleepiness.
So in reality, it was either a strange coincidence or just sheer luck that put him into an eternal sleep. Though mathematicians may try to tell you otherwise, it looks like maths did not really have anything to do with it.