Telephone country code +44 is the United Kingdom, and a number beginning +44 777x is a mobile phone.
(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 United Kingdom. This is a mobile phone.
'00' isn't part of the country code, it is a commonly used international access prefix. Country code +44 is the United Kingdom, and 7797 is a mobile code.
A UK number beginning with +44 7624 (or domestically 07624) is a mobile from the Isle of Man.
+44 is the telephone country code for the United Kingdom, and +44 7506 is a mobile phone prefix, with 6 more digits for the full number.
+447778761808
+4474
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.