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

Cardinal	one hundred
Ordinal	100th (one hundredth)
Factorization
Divisors	2, 4, 5, 10, 20, 25, 50
Roman numeral	C
Unicode representation of Roman numeral	Ⅽ, ⅽ
prefixes	hecto-/hect- (from Greek) centi- (from Latin)
Binary	1100100
Hexadecimal	64
Hebrew	ק (Qof)

In mathematics

One hundred is the square of 10 (in scientific notation it is written as 10²). 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.

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 and a Harshad 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.

In science

• The atomic number of fermium, an actinide.
• In degrees Celsius, the boiling temperature of water at sea level.

In astronomy,

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. The duration of Saros series 100 was 1262.1 years, and it contained 71 solar eclipses.

The Saros number of the lunar eclipse series which began on 403 November 15 and ended on 1864 April 22. The duration of Saros series 100 was 1460.4 years, and it contained 82 lunar eclipses.

In other fields

One hundred is also:

• The number of years in a century.
• 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. dollar with Benjamin Franklin's portrait.
• 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 tiles in a standard Scrabble set.
• The year AD 100 or 100 BC.
• The number of entries in many "all time" lists voted for by the public, e.g. The 100 Best Films, The 100 Worst Pop Songs
• In India, 100 is the police telephone number.
• 120 (see Hundred (word))

Other numbers in the 100s

• One hundred eleven has its own article.
• One hundred seventy four is a semi-meandric number
• One hundred seventy five has its own article.

See also

• hundred (division)
• two hundred