The atomic number of Unnilumium is ______.

According to IUPAC convention for naming of elements with atomic number more than $100$, different digits are written in order and at the end ium is added. For digits following naming is used.

$0-\mathrm{nil}$

$1-\mathrm{un}$

$2-\mathrm{bi}$

$3-\mathrm{tri}$

and so on...