193 - now that East Timor is independent - is probably the safest figure to go with as regards the total number of countries in the world. It depends, you see, on whose list you accept. The American Government, for example, does not recognise Taiwan, but most other countries do. The United Nations does not include the Vatican or Switzerland, though the people of the latter country recently voted to join. (I am not sure whether that has now been completed.) Are Scotland, England and Wales three countries or just one as the bulk of the United Kingdom? And so it goes on.
The figure of 193 includes the Vatican and Switzerland and treats the countries of the UK as one.
Another way to reach a conclusion is to consider the earth's various hemispheres. These are North/South and East/West. Re North/South, the equator cuts through 12 countries, so they may be considered both northern and southern. There are 148 countries solely in the northern hemisphere and 33 solely in the southern. Re East/West, the 0 degrees and 180 degrees lines cut 9 countries - including Britain - so they may be considered both eastern and western. There are 135 countries solely in the eastern hemisphere and 49 solely in the western hemisphere.) A bit of simple arithmetic now shows that a. 12 + 148 + 33 = 193 and b. 9 + 135 + 49 = 193, which is the total number of countries in the world.