78 (number)

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← 77 78 79 →
Cardinalseventy-eight
Ordinal78th
(seventy-eighth)
Factorization2 × 3 × 13
Divisors1, 2, 3, 6, 13, 26, 39, 78
Greek numeralΟΗ´
Roman numeralLXXVIII
Binary10011102
Ternary22203
Quaternary10324
Quinary3035
Senary2106
Octal1168
Duodecimal6612
Hexadecimal4E16
Vigesimal3I20
Base 362636

78 (seventy-eight) is the natural number following 77 and followed by 79.

In mathematics[edit]

78 is:

77 and 78 form a Ruth-Aaron pair.

In science[edit]

In other fields[edit]

78 is also:

  • In reference to gramophone records, 78 refers those meant to be spun at 78 revolutions per minute. Compare: LP, ​33 13 and 45 rpm. 33 + 45 = 78
  • A typical tarot deck containing the 21 trump cards, the Fool and the 56 suit cards make up 78 cards
  • The total number of gifts in the song The Twelve Days of Christmas (since 78 is the 12th triangular number)
  • The Rule of 78s is a method of yearly interest calculation
  • The number of the laps of the Monaco Grand Prix since 1985 (with the exception of 1989 by just 77 laps).
  • The only non-conforming sequenced episode of the Hello Internet podcast written using the Roman numerals LXXVIII.

References[edit]

  1. ^ "Sloane's A007304 : Sphenic numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.
  2. ^ "Sloane's A059756 : Erdős-Woods numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.