round

round is a built-in function in `C source code'.

(round ARG &optional DIVISOR)

Return the nearest integer to ARG.
With optional DIVISOR, return the nearest integer to ARG/DIVISOR.

Rounding a value equidistant between two integers may choose the
integer closer to zero, or it may prefer an even integer, depending on
your machine. For example, (round 2.5) can return 3 on some
systems, but 2 on others.