Nice video to see and recall Euler’s Number for math savvy investors:

It is used to understand continuous compounding interest and in option valuations too (Black-Scholes Formula).

1. Continuous Compounding:

FV = PV e^(rt)

Where:
FV = Future value
PV = Present value
e = 2.718..
r = Interest rate
t = Time in years
​
2. Black-Scholes model; https://www.investopedia.com/terms/b/blackscholes.asp

#Expotential explained: https://www.youtube.com/watch?v=m2MIpDrF7Es