But to be fair, you need to compare the same exact program. A program that handles arbitrary precision isn't the same program as one that doesn't. The same goes for support for missing values and other stuff.
You can verify this for yourself at https://github.com/JuliaLang/julia/blob/master/test/perf/mic...
If it's really idiomatic Python 3 to always use arbitrary precision integers for everything, then it's not really Julia's fault that Python 3 makes it more difficult to use performant arithmetic.