Calculate the Euler Number with more decimal places

[Gribouillis]

You could use a specialized library such as gmpy2

>>> import gmpy2
>>> with gmpy2.local_context(gmpy2.context(), precision=2000) as ctx:
...     e = gmpy2.exp(gmpy2.mpfr('1'))
...     print(e)
... 
2.718281828459045235360287471352662497757247093699959574966967627724076630353547594571382178525166427427466391932003059921817413596629043572900334295260595630738132328627943490763233829880753195251019011573834187930702154089149934884167509244761460668082264800168477411853742345442437107539077744992069551702761838606261331384583000752044933826560297606737113200709328709127443747047230696977209310141692836819025515108657463772111252389784425056953696770785449969967946864454905987931636889230098793127736178215424999229576351482208269895193668033182528869398496465105820939239829488793320362509443117303