29 (number)

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

Cardinal 29
twenty-nine
Ordinal 29th
twenty-ninth
Factorization prime
Divisors 1, 29
Roman numeral XXIX
Binary 11101
Hexadecimal 1D

Contents

[edit] 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 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.

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 x2 + y2 + z2 = 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.

[edit] In science

[edit] Astronomy

  • 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.

[edit] In other fields

Twenty-nine is:

Stephen Colbert declared 29 a stupid number on his show on March 7, 2007.

[edit] Historical years

29 A.D., 29 B.C., 1929, 2029, etc.

[edit] External link