How many country are in Asia?

How many countries are there in Asia? This area is shared by 50 countries. Russia is by far the largest country by area at over 17 million square kilometers and 13 million square kilometers (77%) in Asia. China is the second-largest country with an area of ​​9.6 million square kilometers.

Is there an explanation why there are countries near Asia but is not a part of Asia?

As of now, there are 48 countries in Asia. Maybe there are small Islands not included as part of Asia like Guam, Fiji Islands and so on. They are already a part of US but not in the main territory.