017 is not a country code. Numbers inside a country start like this: Vranje (Serbia), Adolfo - SP (Brazil). 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 |
|---|---|---|
 Vranje · Serbia | +381 17 … | 017 … |
 Adolfo - SP · Brazil | +55 17 … | 017 … |
| Alberto Moreira - SP · Brazil | +55 17 … | 017 … |
| Altair - SP · Brazil | +55 17 … | 017 … |
| 76 more in Brazil | ||
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.