45 (number)
45 (forty-five) is the natural number following 44 and followed by 46.
| Template:Numbers 40s | |
| Cardinal | 45 forty-five |
| Ordinal | 45th forty-fifth |
| Factorization | |
| Divisors | 1, 2, 4, 5, 10, 20 |
| Roman numeral | XLV |
| Binary | 101101 |
| Hexadecimal | 2D |
In mathematics
Forty-five is a triangular number, a hexagonal and 16-gonal number, a Kaprekar number and a Harshad number.
In science
- The atomic number of rhodium
Astronomy
- Messier object M45, a magnitude 1.4 open cluster in the constellation Taurus, also known as the Pleiades
- The New General Catalogue object NGC 45, a magnitude 10.6 spiral galaxy in the constellation Cetus
- The Saros number of the solar eclipse series which began on -1436 March 30 and ended on -156 May 7. The duration of Saros series 45 was 1280.1 years, and it contained 72 solar eclipses.
- The Saros number of the lunar eclipse series which began on -1369 August 19 and ended on 182 March 8. The duration of Saros series 45 was 1550.6 years, and it contained 87 lunar eclipses.
In music
- A type of gramophone record classified by its revolution speed of 45 revolutions per minute (rpm)
- Included in the title of "45 and Fat", a 1996 song by Babybird
- The title of a 2002 song by Elvis Costello, "45", both referring to the 45 rpm singles and to the artist's age when he wrote the song, which was released when he was 47.
- The title of a 2003 song by Shinedown, "45"
In other fields
Forty-five is:
- In years of marriage, the sapphire wedding anniversary.
- 45, the title of a book of essays by record producer Bill Drummond, derived both from the speed of a pop single and from his age when he finished writing it
- Song: "45 Seconds of Ecstasy" by Meatloaf
- The caliber of some handguns and cartridges (see .45)
- A card game: Forty-five
- I-45 is the designation for a US interstate highway in Texas
- The code for international direct=dial phone calls to Denmark
- The '45 refers to the 1745 Jacobite Rising in Great Britain
- The year AD 45, 45 BC, and 1945.
- The forty-fifth edition of the newspaper The North Briton published by John Wilkes, which the government attempted to suppress, later becoming a symbol of support for him
- The forty-five is part of a visual approach into an airport, it is mainly used in general aviation, and in certain conditions, is used by commercial aviation. The pilot must have completed two things before properly entering the forty five. One, he must be three miles from the field, and two, must be at traffic pattern altitude (1000 feet above the ground). Once these two things are complete, he can enter the traffic pattern. The pilot turns into the downwind three-forths of a mile from the runway. These actions are used in GA. The pattern size will be bigger for commercial aviation.
- Stars on 45 sing montages of songs by the Beatles, Beach Boys and other group.
- In 2006, Dusty celebrated 45 years on Cincinnati radio. (currently at oldies 1160 WDJO-AM).
- At age 45, George Foreman became the oldest boxer ever to win the world Heavyweight after knocking out Michael Moorer in the 10th round in Las Vegas on Nov. 5, 1994.
- Cleveland Brown Ernie Davis wore number 45 in the NFL
- Super Bowl XLV, the 45th Super Bowl, will mark the 50th anniversary of the old American Football League, predecessor of the current AFC. The game is scheduled for Feb. 6, 2011.
- Houston Colt 45s (before becoming the Astros)
- Kyle Petty's NASCAR Nextel Cup car number, honoring his late son, Adam Petty.
- Retired uniform number of former pitcher Bob Gibson
- Michael Jordan briefly wore jersey number 45 following his return from his first retirement
- Mets Pedro Martinez wears number 45