285 (number)

← 284 285 286 →
← 200 210 220 230 240 250 260 270 280 290 → List of numbers Integers ← 0 100 200 300 400 500 600 700 800 900 →
Cardinal	two hundred eighty-five
Ordinal	285th (two hundred eighty-fifth)
Factorization	3 × 5 × 19
Divisors	1, 3, 5, 15, 19, 57, 95, 285
Greek numeral	ΣΠΕ´
Roman numeral	CCLXXXV
Binary	1000111012
Ternary	1011203
Senary	11536
Octal	4358
Duodecimal	1B912
Hexadecimal	11D16

285 is the natural number following 284 and preceding 286.

In mathematics

• 285 is an odd composite number. ^[1]
• 285 is the 9th square pyramidal number. That means it is the sum of a number of consecutive perfect squares starting with 1. For 285, it is the sum of all of the single digits' perfect squares. ^[2]
• 285 is the number of variations possible with a binary rooted tree with 13 points. A binary rooted tree means that it always begins with 1 point that is rooted. From there, each point can branch in up to two directions. ^[3]
• 285 is a sphenic number which means that it has three prime factors. ^[4]
• 285 is a Harshad number. That means that it is divisible by the sum of its digits. 285 is divisible by 15. ^[5]
• 285 is a repdigit number in base 7. In base 7, 285 is 555. ^[6]
• 285 is a very symmetric number. If flipped horizontally, these numbers are symmetrical. ^[7]

In technology

• The Turbojet 285 is a variation of the Williams Jet Tenders motorboat that is smaller than its other designs. It is designed for personal use. ^[8]
• In North America, the area code 285 does not exist. If you are receiving a call from a number that begins with 285, it is likely a spam call. ^[9]

World Records

• On December 9, 2022, Peter Thomson received the Guinness World Record for the greatest number of crossovers while jumping rope in a row. ^[10]
• On October 7, 2015, Camelot UK Lotteries Limited achieved the Guinness World Record for the longest champagne cork popping relay. ^[11]
• The Guinness World Record for the greatest number of people in an online video toast chain as of December 16, 2022, is 285. It was achieved in Cereser, Brazil. ^[12]
• On April 12, 2018, the Narraghmore Vintage Club received the Guinness World Record for having the largest parade of 285 tractors

Other fields

• The calendar years 285 AD and 285 BC.
• In the French Republican calendar, The year 285 would be a year 9 cycle and be in 2077. ^[13]
• 285 Regina is a Main belt asteroid that was discovered in 1889 by Auguste Charlois in Nice, France. ^[14]
• In 1980 the 285th Civil Engineering Squadron in the United States Air Force. It is located on the US Virgin Islands. ^[15]
• 285 is the number for several highways in Brazil, Canada, Ireland, Japan, and the United States
  • Interstate Highway 285 in Georgia is listed as one of the most dangerous highways in the United States with 3.5 deaths per 10 miles per year. ^[16]

References

1. "Composite numbers". mathworld.wolfram.com.
2. "Square pyramidal number sequence". marhworld.wolfram.com.
3. "Binary rooted tree". mathworld.wolfram.com.
4. "Sphenic numbers". mathworld.wolfram.com.
5. "Harshad numbers". mathworld.wolfram.com.
6. "Repdigit numbers". mathworld.wolfram.com.
7. Sloane, N. J. A. (ed.). "SequenceA053701(Vertically symmetric numbers)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
8. "Turbojet 285 Williams Jet Tenders motorboat". www.williamsjettenders.com.
9. "Area code 285". www.areacodehelp.com.
10. "Guinness World Record 285 crossovers whil jumping rope". www.guinnessworldrecords.com.
11. "Cork popping relay record". www.guinnessworldrecords.com.
12. "285 people in a video toast chain". www.guinnessworldrecords.com.
13. "French Republican Calendar Guide" (PDF). broadcast.lds.org.
14. "285 Regina". in-the-sky.org.
15. "285th Civil Engineering Squadron". vi.ng.mil.
16. "Interstate 285 is the most dangerous highway in the United States". www.schollelaw.com. 27 September 2021.