Russia and China each border 14 countries. Brazil is a distant 2nd bordering 10 countries. Here is a list of what each country borders.
Russia: Azerbaijan, Belarus, China, Estonia, Finland, Georgia, Kazakhstan, Latvia, Lithuania, Mongolia, North Korea, Norway, Poland, and Ukraine. (This is if you count Kaliningrad, which, although it is not connected to Russia, it is part of Russia nonetheless. If you don't count them as being one together, then Poland and Lithuania do not border Russia.)
China: Afghanistan, Bhutan, India, Kazakhstan, Laos, Mongolia, Myanmar (Burma), Nepal, North Korea, Pakistan, Russia, Tajikistan, and Vietnam.
Brazil: Argentina, Bolivia, Colombia, French Guiana, Guyana, Paraguay, Peru, Suriname, Uruguay, and Venezuela.
Well, there you have it, and a little extra, your most bordered country.
Slovenia shares the largest border with Italy.
No. Turkey does not border the Persian Gulf and is actually smaller than Saudi Arabia, which is the largest country to border the Persian Gulf.
The only country sharing a border with Portugal, that is, Spain
brazil
russiaindia
France
The USA's longest border is with Canada.
I believe that it is Kazakhstan.
CanadaCanada shares the longest border with the US.
The largest country in the world: Canada
India has the largest border with Bangladesh and also has borders with Pakistan, Bhutan, Burma, Nepal and China.
The largest country in the world: Canada