68 (number)

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68 (sixty-eight) is the natural number following 67 and preceding 69

← 60 61 62 63 64 65 66 67 68 69 → List of numbers — Integers 0 10 20 30 40 50 60 70 80 90 →
Cardinal	68 sixty-eight
Ordinal	68th sixty-eighth
Factorization	$2^2 \cdot 17$
Divisors	1, 2, 4, 17, 34, 68
Roman numeral	LXVIII
Binary	1000100
Hexadecimal	44

1 In mathematics
2 In science
- 2.1 Astronomy
3 In other fields
4 In sports
5 Historical years

[edit] 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.

[edit] In science

The atomic number of erbium, a lanthanide

[edit] 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 20. 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 20. The duration of Saros series 68 was 1298.1 years, and it contained 73 lunar eclipses.

[edit] 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
"Summer '68" is a song by Pink Floyd on the album Atom Heart Mother
In the restaurant industry, can mean "add", being the opposite of 86 (number) meaning "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 Slovakia and the Czech Republic