A country code is part of a comprehensive numbering plan, E.164, established by the International Telecommunication Union (ITU), defined to support interoperability among the supported networks of its members. For example, 46 is the country code for Swedish numbers and 1 is the country code for US and Canadian numbers.
The standard defines a country calling code (aka country code) for each state or region which is prefixed to each national numbering plan’s telephone number to support a standard for international destination routing.
