Telephone country codes never begin with zero.
Telephone country code +1, dialed as 00 1 from many places, is North America (USA, Canada, etc.), and 3 is the first digit of a three-digit area code. You need the next two digits to narrow down the location any farther.
Telephone country code +3, dialed as 001 3 from many places, is an incomplete code for somewhere in Europe. You need the next one or two digits to identify the country. For example, +353 is the Republic of Ireland.
To avoid confusion, it is best to write international telephone numbers in correct international format, beginning with the plus symbol and the correct telephone country code (e.g., +1 or +353), 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.
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.
Togo is country code +228.
Liberia is country code +231.
Angola is country code +244.
Mozambique is country code +258.