This number belongs to a high ranking member of the Secret Service.  You could be called because your assistance may be needed in some top secret government program.

The United States Secret Service has an agent with this phone number.  He deals in matters of economic and computer security.  I know this this because I was asked to be flown to a location in international waters to be part of a government program.  I was asked because I have 3 PhD's I suppose... I declined.