155 (number)

	← 150 151 152 153 154 155 156 157 158 159 → List of numbers — Integers ← 0 100 200 300 400 500 600 700 800 900 →
Cardinal	one hundred fifty-five
Ordinal	155th; (one hundred fifty-fifth)
Factorization	5 × 31
Divisors	1, 5, 31, 155
Greek numeral	ΡΝΕ´
Roman numeral	CLV
Binary	100110112
Ternary	122023
Octal	2338
Duodecimal	10B12
Hexadecimal	9B16

155 (one hundred [and] fifty-five) is the natural number following 154 and preceding 156.

In mathematics

155 is:

a composite number
a semiprime.
a deficient number, since 1+5+31)=37<155.
odious, since its binary expansion $10011011_{2}$ has a total of 5 ones in it.

There are 155 primitive permutation groups of degree 81. OEIS: A000019

If one adds up all the primes from the least through the greatest prime factors of 155, that is, 5 and 31, the result is 155. (sequence A055233 in the OEIS) Only three other "small" semiprimes (10, 39, and 371) share this attribute.

In the military

USS Capable (AM-155) was a United States Navy Admirable-class minesweeper during World War II
USS Cole (DD-155) was a United States Navy Wickes-class destroyer during World War II
USS General A. W. Brewster (AP-155) was a United States Navy General G. O. Squier-class transport during World War II
USS Hopping (DE-155) was a United States Navy Buckley-class destroyer escort during World War II
USS Lycoming (APA-155) was a United States Navy Haskell-class attack transport during World War II
USS Mustang (IX-155) was a United States Navy four-master wooden schooner during World War II
155mm artillery, a common caliber

In sports

The maximum possible score in a single break in snooker, with a free ball at the start of the break (147 is the highest possible without a free ball)

In transportation

Alfa Romeo 155, a compact executive car produced from 1992–1998
Seattle Bus Route 155
London Bus Route 155
The British Rail Class 155 is a diesel multiple unit British train
Blériot 155 was a French airliner of the 1920s
155th Street, Manhattan, New York
155th Street New York City Subway stations:

In other fields

155 is also:

The year AD 155 or 155 BC
155 is the number for the International Operator in the United Kingdom
155 AH is a year in the Islamic calendar that corresponds to 771 – 772 CE
155 Scylla is a main belt asteroid
Europium-155 is a radioisotope or Europium and fission product with a half-life of 4.76 years
155, a 2007 song by the band +44
The dialing code for Obihiro, Japan
The atomic number of an element temporarily called unquintquinttium
155 North Wacker is a 46-story skyscraper in Chicago
Wolseley No. 155, Saskatchewan is a rural municipality in Canada

References

External links