29 (number)

29 (twenty-nine) is the natural number following 28 and preceding 30.

Template:Numbers 20s
Cardinal	29 twenty-nine
Ordinal	29th twenty-ninth
Factorization	prime
Roman numeral	XXIX
Binary	11101
Hexadecimal	1D

In mathematics

It is the tenth prime number, and also the third primorial prime, the next prime number as well as primorial prime being thirty-one, with which it comprises a twin prime. Twenty-nine is also the sixth Sophie Germain prime. It is also the sum of three squares, 2² + 3² + 4². It is a Lucas prime, a Pell prime and a tetranacci number. It is an Eisenstein prime with no imaginary part and real part of the form $3n-1$.

None of the first 29 natural numbers have more than two different prime factors. This is the longest such consecutive sequence.

29 is a Markov number, appearing in the solutions to $x^{2}+y^{2}+z^{2}=3xyz$: {2, 5, 29}, {2, 29, 169}, {5, 29, 433}, {29, 169, 14701}, etc.

In science

• The atomic number of copper

In astronomy,

Messier object M29, a magnitude 9.0 open cluster in the constellation Cygnus

The New General Catalogue object NGC 29, a spiral galaxy in the constellation Andromeda

The Saros number 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.

The Saros number 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.

The lunar month is very close to twenty-nine days.

In other fields

Twenty-nine is:

• The number of bones in a normal human skull.
• The number of days February has on leap years.
• The number of letters in the Finnish and Norwegian alphabets.
• The designation of Interstate 29, a U. S. freeway that runs from Missouri to North Dakota.
• In the name of the town Twentynine Palms, California, also the name of the adjoining Marine Corps base, affectionately referred to by Marines as "Twentynine Stumps".
• The number of suras in the Qur'an that begin with muqatta'at
• The highest possible score in a hand of Cribbage.
• Historical years: 29 A.D., 29 B.C., or 1929
• A Rubik's Cube can always be solved in 29 moves or less.
• The most dangerous bus in London according to police statistics

External link

On the number 29 at Wisdom Portal