# 55 (number)

 ← 54 55 56 →
Cardinal fifty-five
Ordinal 55th
(fifty-fifth)
Factorization 5 × 11
Divisors 1, 5, 11, 55
Greek numeral ΝΕ´
Roman numeral LV
Binary 1101112
Ternary 20013
Quaternary 3134
Quinary 2105
Senary 1316
Octal 678
Duodecimal 4712
Vigesimal 2F20
Base 36 1J36

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

## Mathematics

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]

## Music

• "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

• 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