69 (number)

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69 (sixty-nine) is the natural number following 68 and preceding 70.

In mathematics

Adding up the divisors of 1 through 9 gives 69.

Because 69 has an odd number of 1s in its binary representation, it is sometimes called an "odious number" (see Thue-Morse sequence).

It is the largest number whose factorial is less than 10¹⁰⁰ (69! ≈ 1.71x10⁹⁸). This means it is often the largest factorial that can be calculated by a pocket calculator. (See 449.)

It also has the interesting property of being the only number whose square and cube contain once and only once all numerals from zero to nine when written in decimal notation:

• 69² = 4761
• 69³ = 328509

Also, interesting is that 69³² = 6969...

Another interesting property is that 69 is equal to 105 octal, while 105 is equal to 69 hexadecimal. This same property can be applied to all numbers from 64 to 69.

69 is a semiprime.

In astronomy

The Messier object M69 is a magnitude 9.0 globular cluster in the constellation Sagittarius.

In other fields

Sixty-nine is:

• The atomic number of thulium, a lanthanide.
• In the decimal system, the first strobogrammatic square.
• A sex position in which the participants stimulate each others' sex organs with their mouths. This is because the numbers 6 and 9 each represent a human figure with the bottom and the top of each number respectively representing the head of a person, arranged in the same position as required to perform the "69" sex act.
  • Coming from this is the connotation that there are 69 different sexual positions, which is merely a myth.
• Another term for the north-south position in grappling.
• The number of convergence (maybe this name comes from above).
• Part of the title of 69 Année érotique by Serge Gainsbourg.
• A highway route number (see Route 69).
• The registry of the U.S. Navy's nuclear aircraft carrier USS Dwight D. Eisenhower (CVN-69), named after U.S. President Dwight D. Eisenhower.
• Part of the name of a brand of whisky, Vat 69.
• The number of the French department Rhône.
• In Bill & Ted's Excellent Adventure, the number past and present Bill and Ted are thinking of when questioned by future Bill and Ted to confirm their identity (presumably because of its meaning as a sex position).
• The album 69 Love Songs by The Magnetic Fields.
• The title of the novel 69 by Ryu Murakami.
• The highest numbered channel on the UHF analog television broadcast spectrum, after the spectrum previously assigned to channels 70-83 was reallocated for use by cellular phone services.
• The 69 Boyz.
• The 69 Eyes.
• The number of electoral votes received by George Washington when he became the first of the Presidents of the United States.
• 69 or the69er is a professional wrestler in australia. source the69er.comca:Seixanta-nou

es:Sesenta y nueve eo:Sesdek naŭ fr:69 (nombre) ko:69 ia:69 it:Sessantanove lt:69 (skaičius) nl:69 (getal) ja:69 pt:Sessenta e nove ru:69 (число) sl:69 (število) sv:69 (tal) zh:69