What was unique about when Mark Twain born and he died?

When Mark Twain was born (November 30, 1835, Florida, Missouri), 55 years before he died (April 21, 1910) , Halley's Comet was also present on both occasions. Halley's Comet is most famous for being predicted in 1705 by English astronomer Edmond Halley and for its 76-year orbit. Mark Twain made light of these coincidences many times.