Fatto generale: 28 is the number of Chinese constellations, "Xiu" or "mansions" (a literal translation), equivalent to the 12 western zodiac constellations.
Fatto matematico: 28 is the third positive integer with a prime factorization of the form 22q where q is an odd prime.
Trivia: 28 is the number of grams in an ounce (approximately), and used as such in the illegal drug trade.
Data storica: January 28th is the day in 1624 that Sir Thomas Warner founds the first British colony in the Caribbean, on the island of Saint Kitts.