While 447 is not a country code, 44 is the country code for the United Kingdom and its dependencies. Seven is just the first number dialed after the country code.
Most numbers beginning with seven in the United Kingdom are cell phone numbers. It is also assigned to personal numbers and pagers. To dial abroad, one must first dial a prefix number. This number varies from country to country, but it is frequently 00 or 011. The United Kingdom encompasses England, Scotland, Wales and Northern Ireland. The country code also belongs to Guernsey, Jersey and the Isle of Man, which are technically not part of the United Kingdom, but Crown dependencies administered by the British government.