# 27 (number)

27 (twenty-seven) is the natural number following 26 and preceding 28. Twenty-seven is the smallest positive integer requiring four syllables to name in English, though it can be unambiguously defined in just two: "three cubed". It is the first composite number not divisible by any of its digits.

 << 20 21 22 23 24 25 26 27 28 29 >> Cardinal twenty-seven Ordinal twenty-seventh Factorization [itex]3^3 \,\![itex] Roman numeral XXVII Binary 11011 Hexadecimal 1B
 Contents

## In mathematics

Twenty-seven is a perfect cube, being 33 = 3 × 3 × 3. 27 is 3↑↑2 (using Knuth's up-arrow notation). It is also a decagonal number. It is the magic result of a prime reciprocal magic square of the multiples of 1/7. It is a Smith number and a Harshad number. It is the twenty-eighth (and twenty-ninth) digit in π. (3.141592653589793238462643383279502884197169399375105820974944592).

A 10,000-day-old person is 27 years old (and some months).

## In other fields

Twenty-seven is also:

• Art and Cultures
• Countries of the World (http://www.academickids.com/encyclopedia/index.php/Countries)
• Space and Astronomy