Cepheid variables are stars whose regular change of luminosity has a period that correlates with their average luminosity. They are very bright.
Astronomers estimate that there are between 10 sextillion and 1 septillion stars in the visible Universe and 2500 to 3000 stars can be seen at night from Earth.
VY Canis Majoris
VY Canis Majoris, a star that is about 5,000 light years from us, is much larger than our Sun. It could be filled with 7 Billion Suns or 7 Quadrillion Earths.