Bogus number. Not even 1/10th of those are operational. You can't keep tanks sitting in warehouses for years with no maintenance. Seals will rot, batteries will leak, parts will rust, etc.. Additionally, the Russian military has been cannibalizing them for spare parts for decades, and kleptocrats have been stealing other parts and selling them on the black market.
The Russian military is far more "thin" than the perception of the great bear.
I was referring to Kursk during WWII, not the present day Ukraine.