The richest countries in the world are those with the highest GDP per capita. GDP per capita is a measure of a country's economic output divided by its population. It is a useful measure of a country's wealth because it takes into account both the size of the economy and the number of people sharing that wealth.

The richest country in the world in terms of GDP per capita is Luxembourg, with a GDP per capita of \$135,700. Other wealthy nations include Bermuda, Ireland, and Switzerland, all of which have GDPs per capita above $80,000.

There are several factors that contribute to the wealth of a country. These include the size of the economy, the productivity of the workforce, the level of education and health, and the stability of the political and economic system.

The richest countries in the world often have small populations and highly developed economies. They also tend to have a highly skilled workforce and excellent health care and education systems. These factors contribute to high levels of productivity and economic output.

The stability of a country's political and economic system is also important for wealth creation. Countries with stable political and economic systems are more attractive to businesses and investors, which can lead to economic growth.

The wealthiest countries in the world are not without challenges. They face problems such as income inequality, environmental degradation and an aging population. However, they also have the resources to address these challenges and continue to grow their economies.