Country codes beginning +87 are global services, not specific to any country.
+870 = Inmarsat, mostly for ship-to-shore calling
+878 = universal personal numbers
+871 through +874 were formerly used for Inmarsat
+875, +876, and +877 are reserved for maritime satellite phone services
+879 is reserved for an unspecified non-commercial service
Leichtenstein is telephone country code +423.
where is telephone country code 1816
That is not a country code.
The telephone number with the country code +353 is from Ireland. The "87" prefix indicates that it is a mobile phone number. For more specific information about the number itself, such as the owner or location, additional details would be needed.
Telephone country code 353 corresponds to Ireland. The specific code 87 within the 353 country code range is associated with mobile phone numbers in Ireland. Therefore, telephone numbers starting with 87 in Ireland would be mobile phone numbers.
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.