247 (number)
This article is about the number 247. It is not to be confused with 24/7.
| ||||
|---|---|---|---|---|
| Cardinal | two hundred forty-seven | |||
| Ordinal |
247th (two hundred and forty-seventh) | |||
| Factorization | 13 × 19 | |||
| Roman numeral | CCXLVII | |||
| Binary | 111101112 | |||
| Ternary | 1000113 | |||
| Quaternary | 33134 | |||
| Quinary | 14425 | |||
| Senary | 10516 | |||
| Octal | 3678 | |||
| Duodecimal | 18712 | |||
| Hexadecimal | F716 | |||
| Vigesimal | C720 | |||
| Base 36 | 6V36 | |||
247 (two hundred [and] forty-seven) is the natural number following 246 and preceding 248.
In mathematics
247 is:
- a semiprime.
- a brilliant number (the product of two primes with the same number of digits).[1]
- a pentagonal number.[2]
- palindromic in bases 18 (DD18) and 246 (11246).
- a Harshad number in bases 10, 14, 19, 20, 27, 39, 40, 58, 77, 79, 115, 118, 229 and 235.
- the smallest number which can be expressed as the difference between two integers that contain together all digits 0-9. i.e. 247 = 50123 - 49876.[3]
The mathematician and philosopher Alex Bellos suggested in 2014 that a candidate for the lowest uninteresting number would be 247 because it was, at the time, "the lowest number not to have its own page on English Wikipedia".[4]
In other fields
- Sometimes (e.g. when it is used in a URL), 247 is used as an alternative to 24/7, an abbreviation which means "24 hours a day, 7 days a week".
- Approximate number of acres in a square kilometer (1 km2 ≈ 247.10538 acres).
References
- ↑ "Sloane's A078972 : Brilliant numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-28.
- ↑ "Sloane's A000326 : Pentagonal numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-28.
- ↑ Friedman, Erich. "What's Special About This Number?". stetson.edu. Retrieved 15 April 2016.
- ↑ Bellos, Alex (June 2014). The Grapes of Math: How Life Reflects Numbers and Numbers Reflect Life. illus. The Surreal McCoy (1st Simon & Schuster hardcover ed.). N.Y.: Simon & Schuster. pp. 238 & 319 (quoting p. 319). ISBN 978-1-4516-4009-0.
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