It is Euler's number which is the base of natural logarithms.

No, In mathematics and physics, there is a large number of topics named in honor of Leonhard Euler, many of which include their own unique function, equation, formula, identity, number (single or sequence), or other mathematical entity. Unfortunately, many of these entities have been given simple and ambiguous names such as Euler's Law, Euler's function, Euler's equation, and Euler's formula Euler's formula is a mathematical formula that shows a deep relationship between trigonometric functions and the exponential function. Euler's first law states the linear momentum of a body is equal to theproduct of the mass of the body and the velocity of its sentre of mass Euler's second law states that the sum of the external moments about a point is equal to the rate of change of angular momentum about that point.

e isn't a number, its a mathematical constant.

It is sometimes called Euler's number after the mathematician Leonhard Euler.

Euler was a prolific mathematician who answered a large number of questions. You will need to be more specific.