What does e equal?

e, or Euler's number, is roughly equal to 2.718. For more information, see the related link.

e is also used to refer to other properties. In the following famous equation, e refers to energy:

enegy= mass x the speed of light squared which for short is e=mc2

E in the equation "E = mc^2" refers to "Energy".

m refers to mass.

c is the speed of light.