Iztapalapa, and the entire Distrito Federal, is in Mexican area code 55 with Mexico City.
Landline numbers begin with +52 55, followed by an 8-digit local number.
Mobile numbers begin with +52 1 55, followed by an 8-digit mobile number.
(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.)
See the related link.
Here is a list of all telephone area codes ("claves LADA") in Mexico, from the Mexican government: http://www.sre.gob.mx/austin/Util/LadasMexico.html (The column labeled "clave actual" is the current area code. The telephone country code for Mexico is +52, and you must also insert the prefix '1' between the country code and the area code when calling a mobile phone or cell phone.)
There is no area code 678 in Mexico.
There is no telephone area code 185 in Russia.
There is no area code 892 in North America (USA, Canada, etc.). There is no telephone country code +892, nor +89. In Mexico, area code 892 is Cerralvo, Nuevo Leon, and nearby communities in eastern N.L. and northwestern Tamaulipas. Other countries may have a domestic area code 892, but you need to specify which country. For example, "Where in ___(country)__ is telephone area code 892?"
Country code 52 is Mexico.
That depends entirely on which country you're asking about. 0187 or similar is a valid domestic telephone area code in many different countries. There is no telephone area code 0187 in USA, Canada, Mexico, or Australia. UK has area codes 0187x, but they're strewn from Truro to Abergavenny and from Lochmaddy to the Isle of Benbecula; you need one more digit to narrow it down.
There are five different cities named "Morelos" in Mexico, plus the state of Morelos, which has several different telephone area codes. Please specify the city and state. The area code for Cuernavaca, Morelos, is 777. Landline numbers are +52 777; mobile numbers are +52 1 777, with 7 more digits in either case.
The telephone country code for Zimbabwe is +263. The area code for Beitbridge is 0286, or +263 286 in international format.
No, telephone area codes are discrete data.
Telephone country code +93 is Afghanistan, and area code +93 25 (Afghan domestic telephone area code 025) is the city of Logar, south of Kabul.
The telephone country code for Zimbabwe is +263. The area code for Karoi is 064, or +263 64 in international format.