61 (number)
- LXI redirects here, for the electronics association, see LAN eXtensions for Instrumentation.
- For the Cyrillic letter, see Ы.
| 61 | |
|---|---|
| Cardinal | sixty-one |
| Ordinal | 61st (sixty-first) |
| Factorization | prime |
| Divisors | 1, 61 |
| Roman numeral | LXI |
| Binary | 1111012 |
| Octal | 758 |
| Duodecimal | 5112 |
| Hexadecimal | 3D16 |
61 (sixty-one) is the natural number following 60 and preceding 62.
Contents |
In mathematics
It is the 18th prime number. The previous is 59, with which it comprises a twin prime. Sixty-one is a cuban prime of the form 
.
Sixty-one might be the largest prime that divides the product of the next two primes plus 1. If there is a larger such prime, it would have to be greater than 179424673.
Sixty-one is the sum of two squares, 52 + 62, and it is also a centered square number, a centered hexagonal number and a centered decagonal number.
Since 8! + 1 is divisible by 61 but 61 is not one more than a multiple of 8, 61 is a Pillai prime. In the list of Fortunate numbers, 61 occurs thrice, since adding 61 to either the tenth, twelfth or seventeenth primorial gives a prime number (namely 6469693291, 7420738134871 and 1922760350154212639131).
It is also a Keith number, because it recurs in a Fibonacci-like sequence started from its base 10 digits: 6, 1, 7, 8, 15, 23, 38, 61...
In science
The chemical element with the atomic number 61 (promethium), a lanthanide, is the element with the secondary lowest ordinal number, which does not possess any stable isotopes. The promethium preceding element with atomic number 60 (neodymium) and the promethium following element 62 (samarium) have all stable isotopes.
Astronomy
- Messier object M61, a magnitude 10.5 galaxy in the constellation Virgo
- The New General Catalogue object NGC 61, a double spiral galaxy in the constellation Pisces
- The Saros number of the solar eclipse series which began on -973 May 10 and ended on 289 June 5. The duration of Saros series 61 was 1262.1 years, and it contained 71 solar eclipses.
- The Saros number of the lunar eclipse series which began on -870 October 20 and ended on 609 March 26. The duration of Saros series 61 was 1478.4 years, and it contained 83 lunar eclipses.
- 61 Ursae Majoris is located about 31.1 light-years from Sol.[1]
- 61 Cygni was christened the "Flying Star" in 1792 by Giuseppe Piazzi (1746-1826) for its unusually large proper motion. [2]
In other fields
Sixty-one is:
- The number of the French department Orne
- The code for international direct dial phone calls to Australia
- 61*, a 2001 baseball movie directed by Billy Crystal
- The Highway 61 Blues Festival occurs in June in Leland, Mississippi
- Part 61 is a law created by the FAA regarding medical exams. This law has often come under attack by AOPA.
- Highway 61 Revisited is a Bob Dylan album
- The P-61 is the Northrop designed fighter first designated as the XP-61. It first flew on May 26, 1942. It is also known as the Black Widow as it was the first fighter aircraft designed to be a night fighter
- Sixty 1 brand tobacco produced by Nationwide Tobacco
- 61A is the London address of Margot Wendice (Grace Kelly) and Tony Wendice (Ray Milland) in the movie "Dial M for Murder"
- 1 Liberty Place is Philadelphia's tallest building at 61 stories
- The number of points required to win a "standard" game of Cribbage[1]
In sports
- New York Yankees Roger Maris hit 61 home runs in 1961
- Nolan Ryan and Tom Seaver each had 61 career shutouts
- Hockey great Wayne Gretzky holds or shares 61 NHL records (40 for regular season, 15 for Stanley Cup playoff and 6 for All-Star Games)
- Los Angeles Lakers' Elgin Baylor set a record for 61 points in a NBA finals game against the Boston Celtics (April 14, 1962)
- Rotation, a variation of pool, is sometimes called 61
- Richie Evans' NASCAR Whelen Modified Tour car number was 61 until his death in 1985
Historical years
AD 61, 61 BC, 1961, 2061, etc.
References
- R. Crandall and C. Pomerance (2005). Prime Numbers: A Computational Perspective. Springer, NY, 2005, p. 79.
- ^ Hoyle, Edmund Hoyle's Official Rules of Card Games pub. Gary Allen Pty Ltd, (2004) p. 470