91 (NUMBER)

'91' ('ninety-one') is the natural number following 90 and preceding 92.

Cardinal	91 ninety-one
Ordinal	91st ninety-first
Factorization	$7\; cdot\; 13$
Divisors	1, 7, 13, 91
Roman numeral	XCI
Binary	1011011
Hexadecimal	5B

Contents

In mathematics

In science

In other fields

In Sports

References

In mathematics

'Ninety-one' is a triangular number and a hexagonal number, one of the few such numbers to also be a centered hexagonal number, and it is also a centered nonagonal number and a centered cube number. It is the sum of the squares of the first six integers.
It is the smallest positive integer expressible as a sum of two cubes in two different ways if negative roots are allowed: 91 = 6³+(-5)³ = 4³+3³. (See 1729 for more details).
It is also the smallest pseudoprime satisfying the congruence 3^''n'' = 3 mod ''n''.^[1]
91 is a repdigit in base 9 (111).

In science

★ The atomic number of protactinium, an actinide.

★ McCarthy 91 function, a recursive function in discrete mathematics
'In astronomy',
: Messier object M91, a magnitude 11.5 spiral galaxy in the constellation Coma Berenices
: The New General Catalogue object NGC 91, a single star in the constellation Andromeda
:The Saros number of the solar eclipse series which began on August 6 159 BC and ended on 1175 October 16. The duration of Saros series 91 was 1334.2 years, and it contained 75 solar eclipses.
:The Saros number of the lunar eclipse series which began on 161 May 26 and ended on 1459 July 15. The duration of Saros series 91 was 1298.1 years, and it contained 73 lunar eclipses.

In other fields

'Ninety-one' is also:

★ The year AD '91', 91 BC, or 1991.

★ The designation of American Interstate 91, a freeway that runs from Connecticut to Vermont

★ The designation of U.S. Route 91, a north-south highway that runs from Utah to Idaho

★ The code for international direct dial phone calls to India

★ In cents of a U.S. dollar, the amount of money one has if one has one each of the coins of denominations less than a dollar (penny, nickel, dime, quarter and half dollar)

★ The ISBN Group Identifier for books pu]]blished in Sweden.

★ Psalm 91 is known as the Psalm of Protection. It is also the title of a book by Peggy Joyce Ruth

★ "The Gene Autry Show" aired for 91 episodes on CBS from 1950-1956

★ Disney's "Darkwing Duck" aired for 91 episodes from 1991 – 1995

★ TV show "Grounded for Life" aired for 91 episodes on Fox and the WB from 2001 – 2005

★ 91 is a solitaire card game where the object is to move cards, so the top cards total 91.

★ STS-91 Space Shuttle Discovery mission to the International Space Station, June 2, 1998

★ Swedish comic strip

★ The 91st Space Wing (91 SW) is a Minuteman III unit of the United States Air Force, based at Minot Air Force Base, North Dakota

In Sports

'MLB'

★ New York Yankees Joe DiMaggio had 91 hits during his 56-game hitting streak in 1941
'NBA'

★ Chicago Bulls Dennis Rodman wore #91
'NFL'

★ Pittsburgh Steelers Kevin Greene wore #91

★ Buffalo Bills Eric Powell wears #91

★ Chicago Bears Tommie Harris wears #91

★ Cincinnati Bengals Robert Geathers wears #91

★ Detroit Lions Ikaika Alama-Francis wears #91

★ Houston Texans Amobi Okoye wears #91

★ Indianapolis Colts Josh Thomas wears #91

★ Kansas City Chiefs Tamba Hali wears #91

★ Miami Dolphins Vonnie Holliday wears #91

★ New Orleans Saints Will Smith wears #91

★ New York Giants Justin Tuck wears #91

★ New York Jets Sione Pouha wears #91

★ Oakland Raiders Tyler Brayton wears #91

★ Pittsburgh Steelers Aaron Smith wears #91

★ San Diego Chargers Brandon McKinney wears #91

★ Seattle Seahawks Chartric Darby wears #91

★ St. Louis Rams Leonard Little wears #91

★ Tampa Bay Buccaneers Julian Jenkins wears #91

★ Tennessee Titans Travis LaBoy wears #91
'NHL'

★ Buffalo Sabres Clark Gillies wore #91

★ Boston Bruins Marc Savard wears #91

★ Columbus Bluejackets Sergei Fedorov wears #91
'WNBA'

★ Indiana Fever Tamika Whitmore wears #91

References

1. Friedman, Erich. What's Special About This Number?