The department shall examine and determine the genuineness, regularity, and legality of every application for registration of a vehicle, for a certificate of title therefor, and for an operator's or chauffeur's license and of any other application lawfully made to the department, and may in all cases make such investigation as may be deemed necessary or require additional information, and shall reject any such application if not satisfied of the genuineness, regularity, or legality thereof or the truth of any statement contained therein, or for any other reason, when authorized by law.