Twenty-nine (29, XXIX) is the natural number following twenty-eight and preceding thirty. It is the tenth prime number, and also a primorial prime, the next prime number as well as primoral prime being thirty-one, with which it comprises a twin prime. Twenty-nine is also the sum of three squares, 22 + 32 + 42. It is a Lucas number and a Pell number.

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

Twenty-nine is also

See also: twenty-seven, twenty-eight, thirty, thirty-one, integer, list of numbers.

This article is about the number. For the year AD 29, see 29.