Country code +84 is Vietnam. A UK number beginning 0844 (or +44 844) is a special-rate number. It may not be available from outside the UK, and higher rates may apply than for calls to ordinary landline numbers in the UK.here is no area code for (421) within the United States. What you are looking at is an international calling code for Slovakia. Slovakia is located along the border of the Cz … ech Republic near Russia.