Russian has about 360,000,000 million native speakers worldwide.
While most native Russian speakers live in Russian there are a number of countries and regions throughout the world where Russian is a co-official language, such as Belarus. Also, within Russia there are various semi-autonomous territories where other languages enjoy co-official status, such as Tatarstan.
Because Russian has a long history of political centralization, there are not many regional dialectical differences. The Russian spoken in Ukraine is nearly identical to that spoken in even the most eastern parts of Siberia.