25530

The order of the countries is:
Russia
France
Algeria
Serbia
Turkey
Greece
Portugal
Mexico
Venezuela
Italy
New Zealand
Spain
Romania

I started by putting the country names in a random order. Then I read through the clues and started swapping around the countries. When I got to the end of the clues I went back through the clues and checked again. It was nearly right but when I got to clue number 10, I found a mistake.

I wrote out the list of countries with the mistake on one side of a piece of paper. Then I tried to swap some of them so that clue number 10 was right. I asked my brother (a maths pro) but he didn't know. So I stayed up and tried again then i finally found it.