21 Cancri is a double star in the northern zodiac constellation of Cancer.
It is just visible to the naked eye as a dim, red-hued star with an apparent visual magnitude of 6.08.
[2] The star is located around 791 light years away from the Sun, based on parallax.
[6] The brighter component is an aging red giant with a stellar classification of M2III.
[5] It has expanded to 53[6] times the radius of the Sun and is radiating 587[6] times the Sun's luminosity from its swollen photosphere at an effective temperature of 3,885 K.[6] A 9th magnitude companion star is located one arc second away.