28 (number)

Twenty-eight redirects here. This article is relating to number 28. For the years, to see 28 and -28 for 28 av. J. - C.

28 (twenty-eight) is the Entier naturalness which follows 27 and which precedes 29.

In mathematics

It is a made up Nombre, its Diviseur S clean are 1, 2, 4, 7 and 14. What makes a Perfect number of it and a Nombre in harmonic division.

Twenty-eight are the second Perfect number. As a perfect number, it is connected to the number of Mersenne first 7, since $2^2 (2^3 - 1) = 28 \,$ . The following perfect number is 496.

Twenty-eight are a triangular Nombre and a hexagonal Nombre. Twenty-eight are the nap of the five first prime numbers

It is also a Nombre of Keith, because it reproduces in a Suite of Fibonacci which starts with the two figures which composes it in bases 10 (i.e. 2 and 8): 2, 8, 10, 18, 28 …

Twenty-eight are the ninth and last number in the magic first square Indian of order 3.

In other fields

Twenty-eight is:

the Atomic number of the Nickel, a Metal of transition.
the magic fourth Number (physical).
the number of the days in smallest Month of the Gregorian Calendar, February. (Except in the leap years, it comprises some then twenty-nine.)
the Anglo-Saxon common noun (twenty-eight) of the Perroquet Barnardius zonarius semitorquatus , largely widespread in Western Australia and southernmost Australia. Its call resembles “oenniéte” (francized).
the number of letters of the Alphabet S Danish and Swedish.
the number of Constellation S Chinese, “Xiu” or “manors” (a literal translation), equivalent to the 12 constellations of the Western Zodiac.
the normal number of Tooth S of human, by not including the third molars (wisdom teeth).
the number of domino S in a set of standard dominos.
the n° of the French Department of Eure-et-Loir.
the number of years of Marriage of the weddings of Nickel.
the number of the French highway A28 which starts from Abbeville to reach Tours.
historical Years: -28, 28, or 1928.
Ludo

Ru-sib: 28 (число)

Zh-yue: 28

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