ⓘ 129 (number)

                                     

ⓘ 129 (number)

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 {\displaystyle 11^{2}+2^{2}+2^{2}}, 10 2 + 5 2 + 2 {\displaystyle 10^{2}+5^{2}+2^{2}}, 8 2 + 8 2 + 1 2 {\displaystyle 8^{2}+8^{2}+1^{2}}, and 8 2 + 7 2 + 4 2 {\displaystyle 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.

                                     

1. In the military

  • USNS Mission San Miguel T-AO-129 was a United States Navy Mission Buenaventura -class fleet oilers during World War II
  • 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 Donald W. Wolf APD-129 was a Crosley-class high speed transport of the United States Navy
  • Soviet submarine K-129 1960 was a Soviet Pacific Fleet nuclear submarine that sank in 1968
  • USS Vital AM-129 was a United States Navy Auk -class minesweeper for removing naval mines laid in the water
  • 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
                                     

2. In transportation

  • 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.
  • LZ 129 Hindenburg was a German zeppelin which went up in flames while landing on May 6, 1937
                                     

3. 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