Hexakosioihexekontahexaphobia (from Ancient Greek: ἑξακόσιοι ἑξήκοντα ἕξ, romanized: hexakósioi hexēkonta héx, lit. 'six hundred sixty-six') is the fear of the number 666. It comes from the Biblical verse Revelation 13:18, which says that the number 666 is the number of the beast, associated with Satan or the Antichrist.
A well-known example of this fear is Nancy and Ronald Reagan, who, in 1989, when moving to their home in Bel-Air, Los Angeles, had its address changed from 666 St. Cloud Road to 668 St. Cloud Road. Another well-known example was the U.S. Route 666, where accidents and incidents were common. It is known as "Devil's Highway" and renamed to U.S. Route 491.
- Kottler, Jeffrey; David Chen. Stress Management and Prevention: Applications to Daily Life. Cengage Learning. ISBN 978-0-495-11785-8.
- Prayer vigil targets Devil's Day BBC News. Monday, 5 June 2006
- "THE REAGANS: First Family Easing Into Private Life". Los Angeles Times. Nov 19, 1988.
- Ni, Ching-Ching (May 21, 2011). "In Arcadia real estate, 4 is a negative number". Los Angeles Times.
Supporters say changing building numbers isn't such an unusual thing. After all, they say, when President Reagan left office, he and Nancy took up residence at 666 St. Cloud Road in Bel-Air but had the address changed to 668 to avoid the 'number of the beast.'