0231 is not a country code. Numbers inside a country start like this: Baghramyan, Armavir (Armenia), Balţi (Moldova), Dortmund (Germany), Kolhapur, Maharashtra (India) and others. The first digit 0 is the trunk prefix for domestic calls and is dropped from abroad.
Have the full number? Check it in the number lookup.
| Area or operator | From abroad | Inside the country |
|---|---|---|
 Baghramyan, Armavir · Armenia | +374 231 … | 0231 … |
| Echmiadzin, Armavir · Armenia | +374 231 … | 0231 … |
| Echmiadzin/Musaler/Parakar/Zvartnots, Armavir · Armenia | +374 231 … | 0231 … |
| 5 more in Armenia | ||
 Balţi · Moldova | +373 231 … | 0231 … |
 Dortmund · Germany | +49 231 … | 0231 … |
 Kolhapur, Maharashtra · India | +91 231 … | 0231 … |
 Cirebon · Indonesia | +62 231 … | 0231 … |
 Botoșani · Romania | +40 231 … | 0231 … |
If a number starts with +, the first 1–3 digits are the country code. If it starts with 0 (8 in Russia and Kazakhstan), it is a domestic number: an area or operator code follows, and from abroad the 0 or 8 is replaced with + and the country code. The same digits can mean different places, so where the call came from matters.