There is no area code +1 391 in North America (USA, Canada, etc.), nor are there any valid international numbers beginning with +39 1 (+39 is Italy, but there are no numbers beginning with +39 1.). It is possible that there is an area code 391 in some other country.
It is also possible that the 391 number on your caller ID display was faked. Unfortunately for the rest of us, it is very easy for a telemarketer or a criminal to send falsified caller ID information. Be cautious when answering a call if the number on your caller ID is clearly bogus.
(The plus sign means "insert your international access prefix here." From a GSM mobile phone, you can enter the number in full international format, starting with the plus sign. The most common prefix is 00, but North America (USA, Canada, etc.) uses 011, Japan uses 010, Australia uses 0011, and many other countries use different prefixes.)
There is no area code +1 381 in North America (USA, Canada, etc.).
Country code +381 is Serbia.
(The plus sign means "insert your international access prefix here." From a GSM mobile phone, you can enter the number in full international format, starting with the plus sign. The most common prefix is 00, but North America (USA, Canada, etc.) uses 011, and many other countries use different prefixes.)
There is no area code +1 382 in North America (USA, Canada, etc.).
Telephone country code +382 is Montenegro, part of the former Yugoslavia.
(The plus sign means "insert your international access prefix here." From a GSM mobile phone, you can enter the number in full international format, starting with the plus sign. The most common prefix is 00, but North America (USA, Canada, etc.) uses 011, Japan uses 010, Australia uses 0011, and many other countries use different prefixes.)
The country code and area code of Bor, Serbia is 381, (0)30.
The country code and area code of Dakovica, Serbia is 381, (0)390.
The country code and area code of Beograd, Serbia is 381, (0)11.
The country code and area code of Cacak, Serbia is 381, (0)32.
The country code and area code of Jagodina, Serbia is 381, (0)35.
The country code and area code of Kikinda, Serbia is 381, (0)230.
The country code and area code of Kragujevac, Serbia is 381, (0)34.
The country code and area code of Krajevo, Serbia is 381, (0)36.
The country code and area code of Krusevac, Serbia is 381, (0)37.
The country code and area code of Leskovac, Serbia is 381, (0)16.
The country code and area code of Pec, Serbia is 381, (0)39.
The country code and area code of Pirot, Serbia is 381, (0)10.