That's great, I'll add it to my list of useful facts.
Here's another one: 1600, 2000, 2400 are leap years. 1700, 1800, 1900, 2100, 2200, 2300 are not leap years.
and another: September 1752 in the US, Canada and England had only 19 days. Other parts of the world switched in other years.
And one that I remember from MAD Magazine in 1961. It is the last "upside down year" for a long, long, time.