Mongolia is country code +976.
When calling from outside Mongolia, you must drop the initial '0' of the Mongolian domestic number.
Landline numbers served by Mongolia Telecom begin with +976 1, followed by the area code and subscriber number.
Landline numbers served by Mongolian Railway begin with +976 2, followed by the area code and subscriber number.
Mobile numbers begin with +976 9.
(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.)
The ccTLD for Mongolia is ".mn"
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.