0321 is not a country code. Numbers inside a country start like this: Dronten (Netherlands), Noakhali/Chatkhil (Bangladesh), Claro (Colombia), Mojokerto/Jombang (Indonesia) 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 |
|---|---|---|
 Dronten · Netherlands | +31 321 … | 0321 … |
 Noakhali/Chatkhil · Bangladesh | +880 321 … | 0321 … |
 Claro · Colombia | +57 321 … | 0321 … |
 Mojokerto/Jombang · Indonesia | +62 321 … | 0321 … |
 Jazz · Pakistan | +92 321 … | 0321 … |
 Ulricehamn · Sweden | +46 321 … | 0321 … |
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.