55 (number)
For other uses, see 55 (disambiguation).
| ||||
|---|---|---|---|---|
| Cardinal | fifty-five | |||
| Ordinal |
55th (fifty-fifth) | |||
| Factorization | 5 × 11 | |||
| Divisors | 1, 5, 11, 55 | |||
| Roman numeral | LV | |||
| Binary | 1101112 | |||
| Ternary | 20013 | |||
| Quaternary | 3134 | |||
| Quinary | 2105 | |||
| Senary | 1316 | |||
| Octal | 678 | |||
| Duodecimal | 4712 | |||
| Hexadecimal | 3716 | |||
| Vigesimal | 2F20 | |||
| Base 36 | 1J36 | |||
55 (fifty-five) is the natural number following 54 and preceding 56.
Mathematics
55 is the 10th Fibonacci number and a triangular number (the sum of the consecutive numbers 1 to 10). 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) as well as a heptagonal number, and a centered nonagonal number.
In base 10, it is a Kaprekar number.
55 is a semiprime, being the product of 5 and 11 and it is the 2nd member of the (5.q) semiprime family. 55 is one of only two integers with an aliquot sum of 17 (the other being 39). 55 has an aliquot sequence of 4 members: (55, 17, 1, 0).
Other uses
- A 55-gallon drum; see 44 gallon drum
- Numbered car in NASCAR, currently being driven by David Ragan
- The Élysée, the official residency of the French Republic president, which address is 55 rue du Faubourg-Saint-Honoré in Paris.
See also
- 55th Regiment of Foot (disambiguation)
- Channel 55 (disambiguation)
- Type 55 (disambiguation)
- Class 55 (disambiguation)
- Highway 55
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