What are the most populous and least populous areas of russia? and why are some areas more heavily populated than others?

There are no official figures for the population of Russia in 2016, but the 2010 census, the results of which were released in late 2011 and early 2012, reports that the official population of Russia was 142.9 million. The most current estimate for 2019 reports that the population is around 143.90 million.

The Census results are probably the most reliable indicator, but other estimates of the Russia population are available. Rosstat, the official Government statistics agency, suggested that the population of Russia in 2011 was 141.8 million, and the CIA estimated that the population was even lower: 138.7 million.

i dont know but thats a great qusestion