e-Day celebrates the mathematical constant e, which has a value of 2.7182818. It is celebrated on February 7 in countries that follow the month/day (m/d) date format. This is because the first two digits of the date - 2/7 - correspond to the first two digits of the constant.
People living in countries that follow the day/month (d/m) format celebrate it on January 27. The first thee digits of this date - 27/1 - match up with the first three digits of e (2.71).
Also known Euler’s number, after the Swiss mathematician Leonhard Euler, e is an irrational number that represents the idea that all continually growing systems are a scaled version of a common rate. It is mostly used in logarithms, exponential growth, and complex numbers. It is one of the most important numbers in mathematics, including 0, 1 and pi (π).
e is also sometimes called the Napier's Constant and is often incorrectly referred to Euler's Constant. Euler's Constant is denoted by lower case gamma (γ) and has a value of 0.57721.
Other e Days
Many European countries celebrate Euro Day, sometimes also called e Day. The day is observed on January 1 and celebrates the anniversary of the adoption of the Euro, Europe's common currency in 2002. In New Zealand, eDay is a day where people can get rid of e-waste or old electronics such as computers and old appliances, so they can be recycled rather than being placed in a landfill. Engineer’s Day is observed in Paducah, Kentucky on February 21 where many people participate in an egg drop contest, create edible cars and tape people to walls.