68 (number)
| 68 | |
|---|---|
| Cardinal | sixty-eight |
| Ordinal | 68th (sixty-eighth) |
| Factorization |  |
| Divisors | 1, 2, 4, 17, 34, 68 |
| Roman numeral | LXVIII |
| Binary | 10001002 |
| Octal | 1048 |
| Duodecimal | 5812 |
| Hexadecimal | 4416 |
68 (sixty-eight) is the natural number following 67 and preceding 69.
Contents |
In mathematics
Sixty-eight is a nontotient. It is also a Perrin number, preceded in the sequence by 29, 39, 51 (it is the sum of the first two mentioned). It is also a Happy number.
In normal distribution, 68% of values are within one standard deviation from the mean; see 68-95-99.7 rule.
In science
- The atomic number of erbium, a lanthanide
Astronomy
- Messier object M68, a magnitude 9.0 globular cluster in the constellation Hydra
- The New General Catalogue object NGC 68, a spiral galaxy in the constellation Andromeda
- The Saros number of the solar eclipse series which began on -626 March 16 and ended on 685 August. The duration of Saros series 68 was 1280.1 years, and it contained 72 solar eclipses.
- The Saros number of the lunar eclipse series which began on -613 July 3 and ended on 685 August. The duration of Saros series 68 was 1298.1 years, and it contained 73 lunar eclipses.
In other fields
Sixty-eight is:
- In degrees Fahrenheit, the ideal temperature for developing black-and-white film
- The designation of US Interstate 68, a freeway that runs from West Virginia to Maryland
- The registry of the U.S. Navy's aircraft carrier USS Nimitz (CVN-68), named after Admiral Chester Nimitz
- The number of the French department Haut-Rhin
- A publishing house in Canada for exiled Czech authors, 68 Publishers
- In the restaurant industry, it may can mean "put on order", being the opposite of 86 (number) which means "take away"
- The number of sectors on one cylinder of MFM hard disks with 4 heads and 17 sectors per track
- A reference to the Prague Spring of 1968 in Czechoslovakia
- "Summer '68" is a song by Pink Floyd on the album Atom Heart Mother