The opposite - years divisible by 400 are leap years, but other years divisible by 100 but not 400 are not leap years. 2000 was a leap year and it's divisible by 400.

A leap year is a year that has an extra day. This extra day is added at the end of February: February 29th. It's added every four years because Earth does not actually take exactly 365 days to orbit the Sun, but closer to 365 1/4 days. If not for leap years, we'd gradually shift our calendar relative to Earth's orbit.

Ichiro comes to mind.