First of all, it depends on the historical development of human settlement on the planet. However, an important factor can be considered the conditions of the external environment in which people had to live. So the number of population in cold climatic zones is minimal, and where the weather conditions are more favorable, the population is much larger, and, accordingly, the density is also higher.
One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.