Country code +503 (dialed as 00 503 from many places) is El Salvador.
(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.)
El Salvador is country code +503. There are no city codes or area codes. Landline numbers begin with +503 2. Mobile numbers begin with +503 6 or +503 7. The local number is 8 digits, except for freephone and premium-rate numbers.
Country code +503 is El Salvador, and +503 720 xxxxx is a mobile number.
The country code and area code of Hjo, Sweden is 46, (0)503.
Leichtenstein is telephone country code +423.
Telephone country codes never begin with zero.Country code +503, dialed as 00 503 from many places, is El Salvador.To avoid confusion, it is best to write an international telephone number in correct international format, beginning with the plus symbol and the correct telephone country code (e.g., +503), omitting any dialing prefix.(The plus signmeans "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.)
where is telephone country code 1816
That is not a country code.
There is no 909 country code.
There is no telephone country code +897, nor +89, nor any other country code beginning with +89. There are no valid telephone numbers beginning with +89.
Gibraltar is country code +350.
Moldova is country code +373.
Slovenia is country code +386.