February 7th is "e" Day (math)

"e" is one of those amazing numbers that arises naturally in the scheme of things.

Today, 2/7, is celebrated as "e" Day, since the first 2 digits in the number "e" are 2 and 7.

Other special numbers include "pi" (π = 3.141592653..., celebrated on Mar 14th), which is the circumference of any circle divided by its diameter; and "phi" φ = 1.6180339887..., which is the so-called "beauty ratio". These numbers are irrational (that is, their decimals go on forever and never repeat).

e is also an irrational number and it has value:

e = 2.718281828459...

The number e was "discovered" by several mathematicians (Oughtred, Huygens, Jacob Bernoulli, Mercator and Leibniz) but they didn't quite know they had stumbled on it and didn't necessarily know its significance at first.