How big is the largest star in the galaxy?

Among the known stars in the Milky Way, HD 15558 A is the most massive star, its mass is about 152 times that of the sun, its radius is 16.4 times that of the sun, and its luminosity is 660,000 times that of the sun. The known star with the largest mass is R 136a 1 located in large magellanic cloud, and the mass of HD 15558 A is less than half of it. In addition, HD 15558 A belongs to a binary star system, and its companion star is also a massive star with a mass of 46 times and a radius of 5.6 times that of the sun. This binary star system is about 7500 light-years away from the earth and cannot be directly seen by the naked eye. Because of their huge mass, these two stars have short lifetimes and will eventually evolve into stellar black holes.