75 (number)

Last updated
74 75 76
Cardinal seventy-five
Ordinal 75th
(seventy-fifth)
Factorization 3 × 52
Divisors 1, 3, 5, 15, 25, 75
Greek numeral ΟΕ´
Roman numeral LXXV
Binary 10010112
Ternary 22103
Senary 2036
Octal 1138
Duodecimal 6312
Hexadecimal 4B16

75 (seventy-five) is the natural number following 74 and preceding 76.

Contents

In mathematics

75 is a self number because there is no integer that added up to its own digits adds up to 75. [1] It is the sum of the first five pentagonal numbers, and therefore a pentagonal pyramidal number, as well as a nonagonal number. [2] [3]

It is also the fourth ordered Bell number, and a Keith number, because it recurs in a Fibonacci-like sequence started from its base 10 digits: 7, 5, 12, 17, 29, 46, 75... [4]

75 is the count of the number of weak orderings on a set of four items. [5]

Excluding the infinite sets, there are 75 uniform polyhedra in the third dimension, which incorporate star polyhedra as well. Inclusive of 7 families of prisms and antiprisms, there are also 75 uniform compound polyhedra.

In other fields

Seventy-five is:

Related Research Articles

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37 (thirty-seven) is the natural number following 36 and preceding 38.

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300 is the natural number following 299 and preceding 301.

400 is the natural number following 399 and preceding 401.

500 is the natural number following 499 and preceding 501.

700 is the natural number following 699 and preceding 701.

2000 is a natural number following 1999 and preceding 2001.

135 is the natural number following 134 and preceding 136.

151 is a natural number. It follows 150 and precedes 152.

181 is the natural number following 180 and preceding 182.

<span class="mw-page-title-main">5</span> Integer number 5

5 (five) is a number, numeral and digit. It is the natural number, and cardinal number, following 4 and preceding 6, and is a prime number.

20,000 is the natural number that comes after 19,999 and before 20,001.

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14 (fourteen) is a natural number following 13 and preceding 15.

References

  1. Sloane, N. J. A. (ed.). "SequenceA003052". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
  2. Sloane, N. J. A. (ed.). "SequenceA001106". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
  3. Sloane, N. J. A. (ed.). "SequenceA002411". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
  4. Sloane, N. J. A. (ed.). "SequenceA007629". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
  5. Sloane, N. J. A. (ed.). "SequenceA000670". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
  6. “Who are our senators and what do they do?”, Parliament of Canada, retrieved 2014-02-02.