+29 (dialed as 00 29, 011-29, etc.) is an incomplete country code. You need one more digit.
+290 - St Helena and Tristan da Cunha
+291 - Eritrea +295 - discontinued (was assigned but never used for San Marino, now +378)
+297 - Aruba
+298 - Faroe Islands
+299 - Greenland
(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 telephone country code for Zimbabwe is +263. The area code for Juliasdale is 029, or +263 29 in international format.
Leichtenstein is telephone country code +423.
where is telephone country code 1816
That is not a country code.
The telephone country code for Vietnam is +84. The area code for Bac Giang is 0240, or +84 240 in international format.
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.