100 (number)

100 (one hundred) (the Roman numeral is C for centum) is the natural number following 99 and preceding 101.


Cardinal	100 one hundred
Ordinal	100th one hundredth
Factorization	$2^2 \cdot 5^2$
Divisors	2, 4, 5, 10, 20, 25, 50
Roman numeral	C
Unicode representation of Roman numeral	,
prefixes	hecto-/hect- (from Greek)
Binary	1100100
Hexadecimal	64

In mathematics

One hundred is the square of 10 (in scientific notation it is written as

10^2

). The standard SI prefix for a hundred is "hecto-".

It is the sum of the first nine prime numbers, as well as the sum of two prime numbers (47 + 53), and the sum of the cubes of the first four integers. Also, 2⁶ + 6² = 100, thus 100 is a Leyland number.

But perhaps this number is most important as the basis of percentages (literally "per hundred"), with 100% being a full amount.

One hundred is also an 18-gonal number. It is divisible by the number of primes below it, 25 in this case. But it can not be expressed as the difference between any integer and the total of coprimes below it, making it a noncototient.

100 is a Harshad number in base 10, and also in base 4, and in that base it is a self-descriptive number.

In science

100 is the atomic number of fermium, an actinide
100 degrees Celsius is the boiling temperature of pure water at sea level

Astronomy

The Messier object M100, a magnitude 10.5 spiral galaxy in the constellation Coma Berenices.

The New General Catalogue object NGC 100, a magnitude 13.3 spiral galaxy in the constellation Pisces.

The Saros number of the solar eclipse series which began on 264 May 13 and ended on 1526 June 10 with a duration of 1262.1 years and 71 solar eclipses. Further, the number of the lunar eclipse series which began on 403 November 15 and ended on 1864 April 22 with a duration of 1460.4 years, and 82 lunar eclipses.

In other fields

One hundred is also:

The number of years in a century
A 100 year old person is known as a centenarian
The number of pounds in an American short hundredweight
The number of subunits into which many of the world's currencies are divided; for example, one euro is one hundred cents and one Pound Sterling is one hundred pence
The number of verses in the pop song 99 Bottles of Beer
The denomination of the U.S. hundred-dollar bill with Benjamin Franklin's portrait; the "Benjamin" is the largest U.S. bill in print
The denomination of American savings bonds with Thomas Jefferson's portrait
The denomination of American treasury bonds with Andrew Jackson's portrait
The number of the first folder of photos in the DCIM folder created by a brand-new digital camera (or after a change of memory card if the camera is set to auto-reset numbering)
The number of tiles in a standard Scrabble set
In India and Israel, 100 is the police telephone number.
In United Kingdom, 100 is the operator telephone number
Hundred Days, aka the Waterloo Campaign
"The First Hundred Days" is an arbitrary benchmark of a President of the United States' performance at the beginning of his term
The number of poems in the Japanese poetry anthology Hyakunin Isshu
The record number of points scored in one NBA game, set by Wilt Chamberlain on March 2, 1962
100 metres, a racing distance
Historical years: AD 100 or 100 BC.

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In mathematics

In science

Astronomy

In other fields

See also