77521 is a postal code in Baytown, Texas, USA.
- part of Harris County
- 77521 a.k.a. Haemoproteus is a genus of protozoa that are parasitic in birds, reptiles and amphibians. Its name is derived from Greek: Haima, "blood", and Proteus, a sea god who had the power of assuming different shapes. The name Haemoproteus was first used in the description of Haemoproteus columbae in the blood of the pigeon Columba livia by Kruse in 1890. This was also the first description of this genus. Two other genera – Halteridium and Simondia – are now considered to be synonyms of Haemoproteus.
- 77521 a.k.a. Home Fires is a TV program, begun on (22 years ago).