Fatto generale: 189 is the number of irregular verbs in the English language (from "abide" to "write").
Fatto matematico: 189 is a Kaprekar constant in base 2.
Trivia: 189 is the atomic number of an element temporarily called Unoctennium.
Data storica: July 7th is the day in 2005 that a series of four explosions occurs on London's transport system killing 56 people including four alleged suicide bombers and injuring over 700 others.