78 (number)
From Infogalactic: the planetary knowledge core
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|---|---|---|---|---|
| Cardinal | seventy-eight | |||
| Ordinal | 78th (seventy-eighth) |
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| Factorization | 2 × 3 × 13 | |||
| Divisors | 1, 2, 3, 6, 13, 26, 39, 78 | |||
| Roman numeral | LXXVIII | |||
| Binary | 10011102 | |||
| Ternary | 22203 | |||
| Quaternary | 10324 | |||
| Quinary | 3035 | |||
| Senary | 2106 | |||
| Octal | 1168 | |||
| Duodecimal | 6612 | |||
| Hexadecimal | 4E16 | |||
| Vigesimal | 3I20 | |||
| Base 36 | 2636 | |||
78 (seventy-eight) is the natural number following 77 and followed by 79.
In mathematics
With 3 distinct prime factors 78 is a sphenic number. It is an abundant number with an aliquot sum of 90. As a multiple of a perfect number, 78 is itself a semiperfect number.
78 is the 12th triangular number.
77 and 78 form a Ruth-Aaron pair.
Since it is possible to find sequences of 78 consecutive integers such that each inner member shares a factor with either the first or the last member, 78 is an Erdős–Woods number.
In science
- The atomic number of platinum.
In other fields
78 is also:
- In reference to gramophone records, 78 refers those meant to be spun at 78 revolutions per minute. Compare: LP, 33 1⁄3 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
- Municipal Okrug 78, a municipal okrug of Tsentralny District of St. Petersburg, Russia
- NASCAR driver Martin Truex Jr. currently drives the No. 78 Chevrolet SS in the NASCAR Sprint Cup Series.
