E.164 phone number format is the international phone number formatting standard across the globe. The longer the password the more difficult it is to crack it as the number of permutation and combination to guess the password will be too high. Examples of E.164 Numbers +14155552671 The North American Numbering Plan (NANP) divides the territories of its members into numbering plan areas (NPAs) which are encoded numerically with a three-digit telephone number prefix, commonly called the area code. Each telephone is assigned a seven-digit telephone number unique only within its respective numbering plan area. The telephone number consists of a three-digit central office code and a four-digit station number. The combination of an area code and the telephone number serves as a destination routing address in the public switched telephone network (PSTN). Examples of North American Numbering Plan (234) 235-5678 is a valid telephone number; with area code 234, central office prefix (exchange) 235, and line number 5678