171 (number)

In mathematics

In astronomy

• 171P/Spahr is a periodic comet in our solar system
• 171 Ophelia is a main belt asteroid, a member of the Themis family of asteroids

  In geography

• Fox Valley No. 171, Saskatchewan, Canada

  In the military

• 171st Air Refueling Squadron unit of the Michigan Air National Guard flies the KC-135T Stratotanker
• US Air Force 171st Air Refueling Wing Air Mobility Command unit of the Pennsylvania Air National Guard
• 171st Battalion was a unit based in Quebec City, Quebec in the Canadian Expeditionary Force during World War I
• US Army 171st Infantry Brigade based at Fort Jackson, South Carolina
• was a United States Navy following World War I
• was a United States Navy during World War II
• was a United States Navy during World War II
• was a United States Navy during World War II
• was a United States Navy during World War II
• was a United States Navy patrol boat during World War I
• was a United States Navy Storm King-class auxiliary transport during World War II
• Australian Army 171st Aviation Squadron helicopter squadron at Holsworthy Barracks near Sydney

  In the penal code

• Section 171 of the Cyprus Penal code
• Article 171 of the Penal code of Brazil, defines the crime of estelionato. Because of it, in Brazilian Portuguese, um-sete-um became a synonym for "scam", and also "swindler" or "compulsive liar".
• Article 171 of the Philippines Penal Code

  In transportation

• British Rail Class 171
• London Buses route 171
• SMRT Bus Service 171

  In other fields

• The year AD 171 or 171 BC
• E171
• In binary form, the preamble in a Specific Area Message Encoding header in the Emergency Alert System
• The Compaq 171FS computer monitor
• JWH-171, an analgesic drug that acts as a cannabinoid receptor agonist
• Minuscule 171, a Greek minuscule manuscript of the New Testament, on parchment
• SJK 171, one of the earliest New York City graffiti artists of the late 1960s and 1970s
• 171, the Venezuelan emergency telephone number