What Is Hexakosioihexekontahexaphobia?

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What Is Hexakosioihexekontahexaphobia?

Hexakosioihexekontahexaphobia is the fear of the number 666. Related to triskaidekaphobia, or fear of the number 13, this phobia has its origins in both religious belief and superstition.

Hexakosioihexekontahexaphobia is a specific phobia, meaning that someone with this condition would experience intense, irrational anxiety or fear when faced specifically with the number 666. To meet the diagnostic criteria for a specific phobia, your reaction to encountering this number has to be so severe that it's disruptive to your daily life.


The number 666 appears in the Bible, in the Book of Revelation. Revelation 13:17-18 in the King James version states that the “number of the beast” is “six hundred threescore and six,” or 666. This reference appears to be the origin of the fear for some people.

As written, the events depicted in Revelation are extremely frightening. When viewed as a literal transcription of what is to come, it is easy to see how a serious fear or phobia could develop.

Hexakosioihexekontahexaphobia in Pop Culture

The prevalence of the number 666 in pop culture represents another trigger for this fear. Many horror movies use this number as a premise, as do supernatural thrillers that play on the association between the number and the Antichrist. Some films use doomsday scenarios, drawing on the number’s apocalyptic connotations.​

Hexakosioihexekontahexaphobia and Route 666

One of the most famous examples of the fear of the number 666 is the renaming of a famous highway in the American Southwest. U.S. Highway 666 was named according to official guidelines by the American Association of State Highway and Transportation Officials in 1926, as it was the sixth branch off U.S. Highway 66.

Over time, the New Mexico section of Highway 666 proved to be statistically dangerous. In 1986, researchers found that 23% of all crashes involving injury that occurred in the Shiprock District were on a 0.9-mile stretch of Highway 666. Skeptics believe this was due to the road being improperly designed or maintained for increasing traffic loads. However, many believed it was actually the road’s name that caused accidents and fatalities. Highway 666 eventually became known as the Devil’s Highway. It was officially renamed in 2003 to U.S. 491.


As a specific phobia, hexakosioihexekontahexaphobia can include symptoms like:

  • Feeling nauseous or dizzy when encountering the number 666
  • Feeling powerless to control the fear even while understanding that it's unreasonable
  • Having a hard time functioning in daily life due to overwhelming fear
  • Immediate, intense fear when exposed to the number 666
  • Sweating, fast heartbeat, difficulty breathing, or a tight sensation in the chest
  • Taking great steps to avoid the number, often to such an extent that this generates problems in your life

Hexakosioihexekontahexaphobia can manifest in different ways. Since avoidance of the number 666 is a common symptom of the condition, someone with this phobia may go to great lengths to keep themselves from encountering it. That could mean:

  • Driving farther than needed to ensure that their odometer doesn't read 666
  • Refusing to enter buildings with 666 in the address
  • Taking steps to avoid bills that total $6.66, either by adding or subtracting items to change the amount
  • Throwing away debit cards or credit cards that include 666 in the number

Famously, former President Ronald Reagan and his wife, Nancy, changed the street number of their house from 666 to 668 after moving to their post-presidential home in Bel-Air, Los Angeles. It's notable that this change was attributed to Mrs. Reagan's superstition around the number, not hexakosioihexekontahexaphobia.

As with any phobia, symptoms of hexakosioihexekontahexaphobia can range from manageable to severe. In serious cases, you may need to seek professional help.

If you or a loved one are struggling with a mental health condition, contact the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 1-800-662-4357 for information on support and treatment facilities in your area. For more mental health resources, see our National Helpline Database.


Before you're diagnosed with hexakosioihexekontahexaphobia, you will likely go through a thorough clinical interview with a mental health professional. Your doctor may ask about symptoms and will try to determine if you have had any other mental health issues in your past.

Many mental health disorders are diagnosed based on criteria from the Diagnostic and Statistical Manual of Mental Disorders (DSM–5). The DSM-5 lists criteria for specific phobias as a category rather than every single possible fear, so while hexakosioihexekontahexaphobia is not explicitly mentioned in the DSM-5, it is diagnosed the same way that other phobias are.

A key aspect of diagnosing a phobia is the level to which it disrupts daily life. While you may feel uncomfortable with the number 666, it doesn't rise to the level of hexakosioihexekontahexaphobia unless that discomfort leads to fear so intense that it causes noticeable problems in your day-to-day activities.

Your doctor may also look for other conditions that share similar traits, like:


The cause of any phobia can be difficult to determine. In the case of hexakosioihexekontahexaphobia, it may have a cultural component, since the number 666 is viewed negatively in many religious settings. Phobias can also be learned, meaning if a close family member or friend has hexakosioihexekontahexaphobia, you may learn to fear the number as well.


The course of treatment for hexakosioihexekontahexaphobia will largely depend on your goals. Are you trying to resolve conflicting religious views? Do you simply want to stop compulsive phobia-induced behaviors? You may find that medication and/or psychotherapy fit your needs.


Therapy is often a very helpful treatment for phobias. Two common approaches are:

  • Exposure therapy, where you are gradually and repeatedly exposed to the source of your fear while learning how to manage your response
  • Cognitive behavioral therapy (CBT), which combines exposure techniques with therapy to help you learn to recognize and change your phobia-related thought patterns


While psychotherapy is generally the first line of treatment for specific phobias, medication may make sense in some cases. Your doctor may recommend that you take medication initially when you begin treatment or in specific circumstances where you're likely to experience your phobia.

Medication for hexakosioihexekontahexaphobia could include:

  • Benzodiazepines
  • Beta-blockers


As you seek professional help for this phobia, you may still find yourself struggling in your day-to-day life. Mindfulness may help you learn to identify when your anxiety is beginning to intensify so you can try to reduce your stress levels through deep breathing, yoga, meditation, or another intervention.

A Word From Verywell

While hexakosioihexekontahexaphobia is rare, it can cause serious fear and discomfort for people with the condition. It's important to understand that phobias are treatable, and seeking professional help can alleviate your symptoms. If you or a loved one is experiencing debilitating fear due to hexakosioihexekontahexaphobia, consider seeking professional help.

4 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Federal Highway Administration. U. S. 666: “Beast of a highway"?.

  2.  Indian Health Service, Staff Office of Planning, Evaluation and Research. An epidemiologic characterization of motor vehicle crashes on, and an evaluation of geometric design criteria for, U.S. Highway 666, Milepost 92.7 to 93.6, Shiprock, New Mexico.

  3. Substance Abuse and Mental Health Services Administration (SAMHSA). DSM-IV to DSM-5 specific phobia comparison. In: Impact of the DSM-IV to DSM-5 Changes on the National Survey on Drug Use and Health. Rockville, MD: SAMHSA; 2016.

  4. Singh J, Sing J. Treatment options for the specific phobias. Int J Basic Clin Pharmacol. 2016;5(3):593-598. doi:10.18203/2319-2003.ijbcp20161496

Additional Reading

By Lisa Fritscher
Lisa Fritscher is a freelance writer and editor with a deep interest in phobias and other mental health topics.