Nature constant number e is lim(1+1/x)^x, x→+∞ or lim(1+z)^(1/z), z→0, which has a value of about 2.71828 and is one infinite non-cyclic number.

e, as the math constant number, is the Nature logarithms Function Base. It is sometimes called the Euler number, after the Swiss mathematician Euler; There is also a less common name, Napier, in honour of the Scottish math master John Smith. Napier introduced logarithms. Like PI and the imaginary number unit i, e is one of the most important constant numbers in math.