55 (number)

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← 54 55 56 →
Cardinalfifty-five
Ordinal55th
(fifty-fifth)
Factorization5 × 11
Divisors1, 5, 11, 55
Greek numeralΝΕ´
Roman numeralLV
Binary1101112
Ternary20013
Quaternary3134
Quinary2105
Senary1316
Octal678
Duodecimal4712
Hexadecimal3716
Vigesimal2F20
Base 361J36

55 (fifty-five) is the natural number following 54 and preceding 56.

Mathematics[edit]

55 is the 10th Fibonacci number[1] and a triangular number (the sum of the consecutive numbers 1 to 10).[2] It is the largest Fibonacci number to also be a triangular number.

It is a square pyramidal number (the sum of the squares of the integers 1 to 5)[3] as well as a heptagonal number,[4] and a centered nonagonal number.[5]

In base 10, it is a Kaprekar number.[6]

Science[edit]

Astronomy[edit]

Music[edit]

  • "Schfifty Five", a song produced by Gröûp X.[7]
  • The name of a song by British Indie Rock Band Kasabian. The song was released as a B side to Club Foot and was recorded live when the band performed at London's Brixton Academy.
  • "I Can't Drive 55", a song by Sammy Hagar
  • "Ol' '55", a song by Tom Waits
  • Ol' 55 (band), an Australian rock band.
  • Primer 55 an American band
  • Station 55, an album released in 2005 by Cristian Vogel
  • 55 Cadillac, an album by Andrew W.K.

Transportation[edit]

  • In the United States, the National Maximum Speed Law prohibited speed limits higher than 55 miles per hour (90 km/h) from 1974 to 1987

Film[edit]

Years[edit]

Other uses[edit]

See also[edit]

References[edit]

  1. ^ "Sloane's A000045 : Fibonacci numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-30.
  2. ^ "Sloane's A000217 : Triangular numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-30.
  3. ^ "Sloane's A000330 : Square pyramidal numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-30.
  4. ^ "Sloane's A000566 : Heptagonal numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-30.
  5. ^ "Sloane's A060544 : Centered 9-gonal (also known as nonagonal or enneagonal) numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-30.
  6. ^ "Sloane's A006886 : Kaprekar numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-30.
  7. ^ "Group X". Albino Blacksheep. Retrieved 30 July 2018.