55 (number)

← 54 55 56 →
← 50 51 52 53 54 55 56 57 58 59 → List of numbers Integers ← 0 10 20 30 40 50 60 70 80 90 →
Cardinal	fifty-five
Ordinal	55th (fifty-fifth)
Factorization	5 × 11
Divisors	1, 5, 11, 55
Greek numeral	ΝΕ´
Roman numeral	LV, lv
Binary	1101112
Ternary	20013
Senary	1316
Octal	678
Duodecimal	4712
Hexadecimal	3716

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

Mathematics

55 is a square pyramidal number.

55 is composite number ^[1] , and a Fibonacci number ^[2] .

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. The number 55 became a popular shorthand for the 55 mph speed limit. For example, a hand with a pair of fives in Texas hold'em poker is referred to as a "speed limit". ^[3]

References

1. "A002808 - OEIS". oeis.org. Retrieved 2024-11-20.
2. "Sloane's A000045 : Fibonacci numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-30.
3. McComas, Richard (2004-12-05). "400+ Hole Card Hand Names" . Retrieved 2008-10-11.