One example, Canis Majoris has a radius of about 1420 solar radii. But its mass is roughly 17±8 times the mass of the Sun and therefore an average density of 5.33 to 8.38 mg/m3. “It is over 100.000 times less dense than Earth’s atmosphere at sea level.”

https://en.wikipedia.org/wiki/VY_Canis_Majoris

https://nineplanets.org/vy-canis-majoris/