# 27 (number)

27 (twenty-seven; Roman numeral XXVII) is the natural number following 26 and preceding 28.

 ← 26 27 28 →
Cardinaltwenty-seven
Ordinal27th
(twenty-seventh)
Factorization33
Divisors1, 3, 9, 27
Greek numeralΚΖ´
Roman numeralXXVII
Binary110112
Ternary10003
Octal338
Duodecimal2312

## In mathematics

• Twenty-seven is a cube of 3: 33 = 3 × 3 × 3. 27 is also 23 (see tetration). There are exactly 27 straight lines on a smooth cubic surface, which give a basis of the fundamental representation of the E6 Lie algebra. 27 is also a decagonal number.[1]
• In decimal, it is the first composite number not divisible by any of its digits.
• It is the radix (base) of the septemvigesimal positional numeral system.
• 27 is the only positive integer that is 3 times the sum of its digits.
• In a prime reciprocal magic square of the multiples of 1/7, the magic constant is 27.
• In the Collatz conjecture (aka the "3n + 1 conjecture") a starting value of 27 requires 111 steps to reach 1, many more than any lower number.
• The unique simple formally real Jordan algebra, the exceptional Jordan algebra of self-adjoint 3 by 3 matrices of quaternions, is 27-dimensional.[2]
• In decimal, it is a Smith number[3] and a Harshad number.[4]
• It is located at the twenty-eighth (and twenty-ninth) digit after the decimal point in π. (3.141592653589793238462643383279...). If you start counting with 0 it is one of few known self-locating strings in pi.
• 27 contains the decimal digits 2 and 7, and is the result of adding together the integers from 2 to 7 (2 + 3 + 4 + 5 + 6 + 7 = 27)
• There are 27 sporadic groups, if the Tits group is included.
• Within senary, one can readily test for divisibility by 43 (decimal 27) by seeing if the last three digits of the number match 000, 043, 130, 213, 300, 343, 430 or 513.

## In astrology

• 27 Nakṣatra or lunar mansions in Hindu astrology.

## In art

### Music

• "27", a song by Fall Out Boy on the album Folie à Deux
• "27", a song by Passenger on the album Whispers
• "27", a song by Title Fight on the album Shed.[7]
• "27", a song by Biffy Clyro on the album Blackened Sky
• "27", a song on Machine Gun Kelly's album Bloom
• "27 Jennifers", a song by Mike Doughty on the album Rockity Roll
• 27, an album by South Korean singer Kim Sung-kyu
• 27, an album by Argentine rock band Ciro y los Persas
• Twenty-Seven, an album by The Adicts.
• French rapper Kaaris' signature number is 27, from his zipcode 93270.
• "Twenty Seven Strangers" by Villagers.
• 27, a Boston-based band
• 27, an opera by composer Ricky Ian Gordon and librettist Royce Vavrek
• 27 Club, a list of popular musicians, artists, or actors who died at age 27

### Other

• The Minneapolis-based artist Deuce 7 (a.k.a. Deuce Seven, Twenty Seven, 27).

## In sports

• The value of all the colours in snooker add up to 27.
• The number of outs in a regulation baseball game for each team at all adult levels, including professional play, is 27.
• The New York Yankees have won 27 World Series championships, the most of any team in the MLB.

## In other fields

Twenty-seven is also:

## References

1. ^ "Sloane's A001107 : 10-gonal (or decagonal) numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-31.
2. ^ V. G. Kac, "Classification of Simple Z-Graded Lie Superalgebras and Simple Jordan Superalgebras" Communications in Algebra 5 13 (1977): 1380
3. ^ "Sloane's A006753 : Smith numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-31.
4. ^ "Sloane's A005349 : Niven (or Harshad) numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-31.
5. ^ "Dark Energy, Dark Matter | Science Mission Directorate". science.nasa.gov. Retrieved 2020-11-08.
6. ^ "SpanishDict Grammar Guide". SpanishDict. Retrieved 2020-08-19.
7. ^
8. ^ Steve Jenkins, Bones (2010), ISBN 978-0-545-04651-0
9. ^ "Is there more reward if the congregation is greater? - Islam Question & Answer". islamqa.info. Retrieved 2020-02-09.