129 (number)

129 (one hundred [and] twenty-nine) is the natural number following 128 and preceding 130.

← 128 129 130 →
← 120 121 122 123 124 125 126 127 128 129 → List of numbers Integers ← 0 100 200 300 400 500 600 700 800 900 →
Cardinal	one hundred twenty-nine
Ordinal	129th (one hundred twenty-ninth)
Factorization	3 × 43
Divisors	1, 3, 43, 129
Greek numeral	ΡΚΘ´
Roman numeral	CXXIX
Binary	100000012
Ternary	112103
Senary	3336
Octal	2018
Duodecimal	A912
Hexadecimal	8116

In mathematics

129 is the sum of the first ten prime numbers. It is the smallest number that can be expressed as a sum of three squares in four different ways: $11^{2}+2^{2}+2^{2}$, $10^{2}+5^{2}+2^{2}$, $8^{2}+8^{2}+1^{2}$, and $8^{2}+7^{2}+4^{2}$.

129 is the product of only two primes, 3 and 43, making 129 a semiprime. Since 3 and 43 are both Gaussian primes, this means that 129 is a Blum integer.

129 is a repdigit in base 6 (333).

129 is a happy number.

129 is a centered octahedral number.

In the military

• Raytheon AGM-129 ACM (Advanced Cruise Missile) was a low observable, sub-sonic, jet-powered, air-launched cruise missile used by the United States Air Force
• Soviet submarine K-129 (1960) was a Soviet Pacific Fleet nuclear submarine that sank in 1968
• USNS Mission San Miguel (T-AO-129) was a United States Navy Mission Buenaventura-class fleet oilers during World War II
• USS Donald W. Wolf (APD-129) was a Crosley-class high speed transport of the United States Navy
• USS Edsall (DE-129) was the lead ship of her class of destroyer escort in the United States Navy
• USS Marvin H. McIntyre (APA-129) was a United States Navy Haskell-class attack transport during World War II
• USS Phobos (AK-129) was a United States Navy Crater-class cargo ship during World War II
• USS Vital (AM-129) was a United States Navy Auk-class minesweeper for removing naval mines laid in the water
• Agusta A129 Mangusta is an attack helicopter originally designed and produced by Italian company Agusta
• The 129th Rescue Wing (129 RQW) is a unit of the California Air National Guard

In transportation

• LZ 129 Hindenburg was a German zeppelin which went up in flames while landing on May 6, 1937
• London Buses route 129 is a Transport for London contracted bus route in London
• STS-129 was a Space Shuttle mission to the International Space Station, flown in November 2009 by the shuttle Atlantis.

In other fields

129 is also:

• The year AD 129 or 129 BC
• 129 AH is a year in the Islamic calendar that corresponds to 746–747 CE
• 129 Antigone is a main belt asteroid
• The atomic number of unbiennium, an element yet to be discovered
• A film format: 129 film
• Sonnet 129 by William Shakespeare

See also

• List of highways numbered 129
• United Nations Security Council Resolution 129