7

This number is a prime.

Just showing those entries submitted by 'Das': (Click here to show all)

+ Seven is the only odd prime that becomes "even" by deleting a letter. [Beedassy]

+ In most Hindu marriages the bride follows the groom 7 times around the holy fire, which is called a Saptapadi. [Das]

+ Whilst every Fibonacci prime number has odd prime subscript, 7 is the first prime not appearing in the Fibonacci sequence. [Beedassy]

+ The smallest prime NSW number. [Beedassy]

+ It is possible to construct an angle of π/7 using 7 matchsticks. [Beedassy]

+ The smallest prime subscript n such that pn+1 is the first prime dividing #pn+1, (pn being the nth prime ). [Beedassy]

+ The normal human head bears 7 sense organ openings: 2 eye sockets, 2 ear canals, 2 nostrils, and a mouth. [Beedassy]

+ The largest known prime p such that p! + 1 is the square of a prime. [Beedassy]

+ The only odd prime p whose n-th power pn, for any nonzero n below p, has exactly n digits. [Beedassy]

+ The number of distinct four of fewer face-joined unit cubes forming the polycube pieces of the 3-by-3-by-3 Soma cube dissection puzzle invented by Piet Hein in 1936. [Beedassy]

+ The only known number whose factorial has 50% of its digits consisting of 0's: 7! = 5040. [Beedassy]

+ H-7 is the heaviest isotope of hydrogen observed experimentally in a heavy particle accelerator. [Beedassy]

+ The French version of the popular cartoon Spot the difference puzzle is called "Le jeu des 7 erreurs" (meaning 'The 7 mistakes game'). [Beedassy]

+ The standard ASCII (American Standard Code for Information Interchange) character codes for encoding symbols on a typical American keyboard were originally 7 bits long. [Beedassy]

+ Number Theorist James Maynard received an award by The European Mathematical Society for his 2016 paper in which he proved there are infinitely many primes devoid of any one of the digits, and he used the rare property of primes without digit 7 as a test case. [Beedassy]

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