29  

Cardinal  twentynine 
Ordinal  29th (twentyninth) 
Factorization  prime 
Divisors  1, 29 
Roman numeral  XXIX 
Binary  11101_{2} 
Octal  35_{8} 
Duodecimal  25_{12} 
Hexadecimal  1D_{16} 
29 (twentynine) is the natural number following 28 and preceding 30.
Contents 
It is the tenth prime number, and also the fourth primorial prime. It forms a twin prime pair with thirtyone, which is also a primorial prime. Twentynine is also the sixth Sophie Germain prime. It is also the sum of three consecutive squares, 2^{2} + 3^{2} + 4^{2}. 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.
Twentynine is the aliquot sum of the odd discrete biprimes 115 and 187 and is the base of the 29aliquot 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 29^{2} + 1 = 842 is 421, which is obviously more than 29 twice, 29 is a Størmer number.
Twentynine is:
29 B.C., 29 A.D., 1929, 2029, etc.
Twentynine is a number. It comes between twentyeight and thirty, and is an odd number. It is also the 10th prime number, after 2, 3, 5, 7, 11, 13, 17, 19, and 23.
