I think BC's features are equivalent to:

- Python's native integer handling, which already has no size limit.

- PLUS part of the Decimal module in Python's stdlib: BC's floats are DECIMAL by default, not binary.

- PLUS an implementation of Bessel's J function, while neglecting Bessel's K.

- Some features for base conversion using `ibase` and `obase`. So, I suppose you can output numbers to base 60. [EDIT: Correction from earlier: ibase is allowed to be at most 16, while POSIX allows for the maximum value of obase to be at least 99, which therefore does allow for formatting output to base 60.]