29 is the natural number following 28 and preceding 30.
- It is the tenth prime number, and also the fourth 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. 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.
- 29 is a Markov number, appearing in the solutions to x + y + z = 3xyz:,,,, etc.
- 29 is a Perrin number, preceded in the sequence by 12, 17, 22.
- 29 is the smallest positive whole number that cannot be made from the numbers, using each exactly once and using only addition, subtraction, multiplication, and division.
- It is the number of pentacubes if reflections are considered distinct.
- The Bishnois community follows 29 principles. Guru Jambheshwar 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.
- The number of suras in the Qur'an that begin with muqatta'at.
Science and astronomy
- The atomic number of copper.
- Messier object M29, a magnitude 6.6 open cluster in the constellation Cygnus.
- The New General Catalogue NGC 29, a spiral galaxy in the constellation Andromeda.
- The lunar month is very close to twenty-nine days.
- Saturn requires over 29 years to orbit the Sun.
- The number of days February has in leap years.
Language and literature
- The number of letters in the Turkish, Finnish, Swedish, Danish and Norwegian alphabets
- The number of Knuts in one Sickle in the fictional currency in the Harry Potter novels
- In the name of the town Twentynine Palms, California
- The number of the French department of Finistère
- 29th Regiment of Foot, a former regiment in the British Army
- Marine Corps Air Ground Combat Center Twentynine Palms, affectionately referred to by Marines as "Twentynine Stumps".
- Boeing B-29, a large bomber
Music and entertainment
- "$29.00" is a song on the album Blue Valentine by Tom Waits.
- 29, an album by Ryan Adams.
- "No. 29", a song about a washed-up high school football star from the album Exit 0 by Steve Earle.
- The track from which the Chattanooga Choo Choo train departs in the Glenn Miller song.
- The number of attributes existing according to The Strokes in "You Only Live Once".
- A track from Bon Iver's album, 22, A Million, all tracks being numerically themed.
- The 29er sailing skiff is a high-performance two-handed yacht.
- A 29er is a mountain bike with 29-inch wheels.
- 29 is the highest possible score in a hand of Cribbage or Khanhoo.