Telephone country codes never begin with zero.
Telephone country code +68, dialed as 00 68 from many places, is an incomplete code for an island in the Pacific Ocean. You need one more digit to determine the country.
Telephone country code +8, dialed as 006 8 from many places, is an incomplete code for somewhere in Asia, or for a transnational telephone service. You need at least one or two more digits to determine which one.
To reduce the possibility of confusion, it is best to quote an international telephone number beginning with the single plus symbol and the correct telephone country code (e.g., +685 or +886), 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.
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.