Telephone country codes never begin with zero.
Country code +299, dialed as 00 299 from many places, is Greenland.
Country code +99, dialed as 002 99 from many places, is an incomplete code for one of the former Soviet republics in Central Asia, or for a transnational telephone service. You need one more digit to identify the country or service. For example, +992 is Tajikistan.
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., +299 or +992), 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.)
Leichtenstein is telephone country code +423.
where is telephone country code 1816
That is not a 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.
Niue is country code +683.