bignum as the default integer is quite common in lots of languages[1]. Notably, Lisp, Scheme, Erlang, Python.

Scheme is a bit interesting in that they have a "numeric tower", which contains rationals and even complex numbers (implementations were free to implement a subset of this tower, at least as far as R5RS, not sure today)

[1] https://en.wikipedia.org/wiki/List_of_arbitrary-precision_ar...