27

27 (twenty-seven) is a postive integer preceded by 26 and followed by 28.

It is an odd number, and a multiple of 3 and 9.

27 is a special number in googology because it occurs naturally in googological functions base on the hyper-operators, such as BEAF, but also occurs frequently in Conway Chain Arrows. This is because 27 is 3^3, or 3{3}3 in Bowers' old Extended Operator notation, thus it can be expressed as {3,3,3} in Bowers' original array notation.

27 is also a Steinhaus Triangle, being equal to triangle(3).