Method and apparatus for managing telephone number, and computer product

A storing unit stores a regular telephone number of a user and a provisional telephone number corresponding to the regular telephone number. An acquiring unit acquires a provisional telephone number of a receiver and a regular telephone number of a caller who called at the provisional telephone number of the receiver. A searching unit searches a regular telephone number corresponding to the provisional number of the receiver from the storing unit. A call establishing unit establishes a call between the caller and the receiver corresponding to the regular telephone number searched.