Telephone country codes never begin with zero.
Telephone country code +1, dialed as 00 1 from many places, is North America (USA, Canada, etc.); 55 is the first two digits of a three-digit area code, but you need the next digit to narrow down the location.
Telephone country code +55, dialed as 001 55 from many places, is Brazil.
To reduce the possibility for confusion, it is best to write an international telephone number beginning with the plus symbol and the correct telephone country code (e.g., +1 or +55), omitting any dialing prefix.
(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.
Fiji has telephone country code +679.
Country code +57 is Colombia.
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.
Liberia is country code +231.