|Cardinal||one hundred seventy-three|
(one hundred seventy-third)
- an odd number.
- a deficient number.
- an odious number.
- a balanced prime.
- an Eisenstein prime with no imaginary part.
- a Sophie Germain prime.
- an inconsummate number.
- the sum of 2 squares: 22 + 132.
- the sum of three consecutive prime numbers: 53 + 59 + 61.
- palindromic in bases 3 (201023), 9 (2129) and 172 (11172).
- 173 Ino is a large dark main belt asteroid
- 173P/Mueller is a periodic comet in our solar system
- Arp 173 (VV 296, KPG 439) is a pair of galaxies in the constellation Boötes
In the military
- 173rd Air Refueling Squadron unit of the Nebraska Air National Guard
- 173rd Airborne Brigade Combat Team of the United States Army based in Vicenza
- 173rd Battalion unit of the Canadian Expeditionary Force during the World War I
- 173rd Surveillance Squadron (Australia) of the Australian Army at Oakey, Queensland
- K-173 Chelyabinsk Russian Oscar-class submarine
- USNS Provo (T-AG-173) was a U.S. Navy Phoenix-class auxiliary ship following World War II
- USS Codington (AK-173) was a U.S. Navy Alamosa-class cargo ship during World War II
- USS Eldridge (DE-173) was a U.S. Navy Cannon-class destroyer escort during World War II
- USS Etamin (IX-173) was a U.S. Navy Crater-class cargo ship during World War II
- USS Florence (SP-173) was a U.S. Navy yacht during World War I
- USS Hyde (APA-173) was a U.S. Navy Haskell-class attack transport ship during World War II
- USS PC-472 was a 173-foot (53 m) U.S. Navy submarine chaser during World War II
- USS Pike (SS-173) was a U.S. Navy Porpoise-class submarine during World War II
- USS Sproston (DD-173) was a U.S. Navy Wickes-class destroyer following World War II
- Vought V-173 (Flying Pancake) was a U.S. Navy experimental test aircraft during World War II
- The Georgia Railroad, the world longest railroad in 1845, ran for 173 miles (278 km) from Augusta to Marthasville (Atlanta, Georgia)
- United Airlines Flight 173 en route from Denver to Portland crashed on December 28, 1978
- The Velocity 173 was a kit aircraft produced by Velocity Aircraft in the early '90s.
In other fields
173 is also:
- The year AD 173 or 173 BC
- 173 AH is a year in the Islamic calendar that corresponds to 789 – 790 CE
- The atomic number of an element temporarily called Unsepttrium
- The book "173 Hours in Captivity" (2000)
- Topic of discussion during the podcast "Skeptics with a K" episode 180 
- List of highways numbered 173
- United Nations Security Council Resolution 173
- United States Supreme Court cases, Volume 173
|Wikimedia Commons has media related to 173 (number).|
- "Sloane's A006562 : Balanced primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-26.
- "Sloane's A005384 : Sophie Germain primes". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-26.
- "Sloane's A003635 : Inconsummate numbers in base 10". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-26.
- Michael Marshall (August 25, 2016). "Skeptics with a K: Episode #180". www.merseysideskeptics.org.uk/podcasts/ (Podcast). Merseyside Skeptics Society. Event occurs at 0:59:15-1:01:30. Retrieved 15 November 2016.