29 (number)

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

In mathematics

It is the tenth prime number, and also the third primorial prime. It forms a twin prime pair with thirty-one, which is also a primorial prime. Twenty-nine is also the sixth Sophie Germain prime. It is also the sum of three consecutive 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 $3n-1$ . Since 18! + 1 is a multiple of 29 but 29 is not one more than a multiple 18, 29 is a Pillai prime. 29 is also the 10th supersingular prime.

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

Twenty-nine is the aliquot sum of the odd discrete biprimes 115, and 187 and is the base of the 29-aliquot tree.

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.

29 is a Perrin number, preceded in the sequence by 12, 17, 22.

Since the greatest prime factor of 29² + 1 = 842 is 421, which is obviously more than 29 twice, 29 is a Størmer number.

The Bishnoi community follow 29 principles. Guru Jambheshwar ji had laid down 29 principles to be followed by the sect in 1485 A.D. In Hindi, Bish means 20 and noi means 9; thus, Bishnoi translates as Twenty-niners. One of his 29 principles states "JEEV DAYA PALNI, RUNKH LIL0 NAHI GHAVE" which means to protect trees and animals, thus trees and animals are considered to be sacred by the Bishnois.

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.

Twenty-nine is:

The number of days February has in leap years.
The number of letters in the Turkish,^[1] Finnish,^{[citation needed]} Faroese]],^{[citation needed]} Faroese and Norwegian^[2] 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 Air Ground Combat Center Twentynine Palms, affectionately referred to by Marines as "Twentynine Stumps".^[3]
The number of suras in the Qur'an that begin with muqatta'at
The highest possible score in a hand of Cribbage.
An album by Ryan Adams.
The track the Chattanooga Choo Choo leaves in the Glenn Miller song.
29th Regiment of Foot, a former regiment in the British Army.
The retired jersey number of Rod Carew
The 2008 Summer Olympic Games

^ Caroline Finkel, Osman's Dream. New York: Basic Books (2006): xv. "The modern Turkish alphabet has 29 letters, of which three vowels and three consonants are unfamiliar to those who do not know the language, and one consonant is pronounced differently from English."
^ Anthony Ham, Miles Roddis & Graeme Cornwallis, Norway. New York: Lonely Planet (2005): 413. "The modern Norwegian alphabet has 29 letters: those used in English, plus the vowels æ, ø and a (which are listed at the end of the alphabet)."
^ Stephen F. Tomajczyk, To Be a U.S. Marine. New York: Zenith Imprint (2004): 155. "Twenty-nine stumps—Slang for Twenty-nine Palms Marine Corps Air-Ground Combat Center, located in California's Mojave Desert."