29 (twenty-nine) is the natural number following 28 and preceding 30.
In mathematics
It is the tenth prime number, and also a primorial prime, the next prime number as well as primoral prime being thirty-one, with which it comprises a twin prime. Twenty-nine is also a Sophie Germain prime. It is also the sum of three squares, 22 + 32 + 42. It is a Lucas number, a Pell number and a tetranacci number.
None of the first 29 natural numbers have more than two different prime factors. This is the longest such consecutive sequence.
In science
In astronomy,
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Messier object M29, a magnitude 9.0 open cluster in the constellation Cygnus
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The New General Catalogue object http://www.ngcic.org/ NGC 29 , a spiral galaxy in the constellation Andromeda
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The Saros number http://sunearth.gsfc.nasa.gov/eclipse/SEsaros/SEsaros1-175.html of the solar eclipse series which began on -1881 March 1 and ended on -583 April 19. The duration of Saros series 29 was 1298.1 years, and it contained 73 solar eclipses.
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The Saros number http://sunearth.gsfc.nasa.gov/eclipse/LEsaros/LEsaros1-175.html of the lunar eclipse series which began on -1814 July 21 and ended on -317 January 5. The duration of Saros series 29 was 1496.5 years, and it contained 84 lunar eclipses.
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The lunar month is very close to twenty-nine days.
In other fields
Twenty-nine is:
Last updated: 05-03-2005 17:50:55
