71 (number): Difference between revisions

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71 (seventy-one) is the natural number following 70 and preceding 72.

Look up seventy-one in Wiktionary, the free dictionary.

In mathematics

71 is:

• the algebraic degree of Conway's constant, a remarkable number arising in the study of look-and-say sequences.
• the 20th prime number. The next is 73, with which it composes a twin prime.
• a permutable prime with 17.
• is the largest number which occurs as a prime factor of an order of a sporadic simple group.
• a centered heptagonal number.^[1]
• an Eisenstein prime with no imaginary part and real part of the form 3n – 1.
• a Pillai prime, since 9! + 1 is divisible by 71 but 71 is not one more than a multiple of 9.^[2]
• the largest (15th) supersingular prime, which is also a Chen prime.^[3]
• part of the last known pair (71, 7) of Brown numbers, since 71² = 7! + 1.
• the twenty-third term of the Euclid–Mullin sequence, as it is the least prime factor of one more than the product of the first twenty-two terms.^[4]
• the smallest positive integer d such that the imaginary quadratic field Q(√–d) has class number = 7.^[5]

If we add up the primes less than 71 (2 through 67), we get 568, which is divisible by 71, 8 times.

In science

• The atomic number of lutetium, a lanthanide

In astronomy

• Messier object M71, a magnitude 8.5 globular cluster in the constellation Sagitta
• The New General Catalogue object NGC 71, a magnitude 13.2 peculiar spiral galaxy in the constellation Andromeda

In other fields

Seventy-one is also:

• The number of different characters that can be used with a standard English Keyboard, excluding uppercase letters.
• The designation of USA Interstate 71, which runs from Kentucky to Ohio.
• The registry of the U.S. Navy's nuclear aircraft carrier USS Theodore Roosevelt (CVN-71), named after U.S. President Theodore Roosevelt.
• The number of the French department Saône-et-Loire.
• The year AD 71, 71 BC, or 1971.
• In the Mexican television sitcom, El Chavo del Ocho, Doña Clotilde lives in the apartment number 71, being therefore known as "Bruja del 71".
• Lockheed SR-71 Blackbird long-range, Mach 3 strategic reconnaissance aircraft
• "71 Fragments of a Chronology of Chance," a film by Michael Haneke
• 71: Into the Fire, South Korean film about the Korean War
• The form number for the United States Office of Personnel Management for requesting a leave of absence.
• Municipal Okrug #71, name of Volkovskoye Municipal Okrug of Frunzensky District of Saint Petersburg, Russia, before 2008
• The Irish Rail 071 Class diesel locomotive.
• In the Jason Bourne novels by American author Robert Ludlum the department within the CIA which made Bourne and the other super agents is called Treadstone Seventy-One.
• SR-71 is an American Alternative Rock band.
• The number of the laps of the Austrian Grand Prix, Mexican Grand Prix, and Brazilian Grand Prix.
• The Institutional Revolutionary Party ruled the Mexico for 71 years (1929–2000)

References