Country code +55 (dialed as 00 55 from many places) is Brazil.
Area codes in Brazil are two digits, followed by an 8-digit landline number or an 8- or 9-digit mobile number. Landlines and mobiles use the same area codes, but the subscriber number begins with 2, 3, 4, or 5 for landlines, or 6, 7, 8, or 9 for mobiles. For example, +55 11 2xxx xxxx is a landline in São Paulo (area code 11), but +55 11 9xx xxx xxx is a mobile in São Paulo.
(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.)
Leichtenstein is telephone country code +423.
where is telephone country code 1816
That is not a country code.
Country code +57 is Colombia.
Country code 52 is Mexico.
Fiji has telephone country code +679.
Gibraltar is country code +350.
Moldova is country code +373.
Slovenia is country code +386.
Vanuatu is country code +678.
Niue is country code +683.
Togo is country code +228.