209 (number)
Encyclopedia
209 is the natural number
following 208
and preceding 210
. It is written as "two hundred and nine".
Natural number
In mathematics, the natural numbers are the ordinary whole numbers used for counting and ordering . These purposes are related to the linguistic notions of cardinal and ordinal numbers, respectively...
following 208
208 (number)
208 is the natural number following 207 and preceding 209. It may be written as "two hundred eight" or "two hundred and eight".-In mathematics:* 208 is a tetranacci number* 208 is the sum of the squares of the first five primes-In other fields:...
and preceding 210
210 (number)
210 is the natural number following 209 and preceding 211.- In mathematics :210 is a composite number, an abundant number, and the product of the first four prime numbers , and thus a primorial...
. It is written as "two hundred and nine".
In mathematics
- 209 is a highly cototient numberHighly cototient numberIn number theory, a branch of mathematics, a highly cototient number is a positive integer k which is above one and has more solutions to the equation...
- 209 is a Harshad numberHarshad numberA Harshad number, or Niven number in a given number base, is an integer that is divisible by the sum of its digits when written in that base. Harshad numbers were defined by D. R. Kaprekar, a mathematician from India. The word "Harshad" comes from the Sanskrit + , meaning joy-giver. The Niven...
- 209 is a self numberSelf numberA self number, Colombian number or Devlali number is an integer which, in a given base, cannot be generated by any other integer added to the sum of that other integer's digits. For example, 21 is not a self number, since it can be generated by the sum of 15 and the digits comprising 15, that is,...
- 209=16+25+34+43+52+61
In other fields
- 209 Dido209 Dido209 Dido is a very large main-belt asteroid. It is classified as a C-type asteroid and is probably composed of privitive carbonaceous materials. Like many asteroids of its type, it has an extremely low albedo.It was discovered by C. H. F...
is a very large main-belt asteroid. - The 209 series is a commuter EMU used by East Japan Railway Company on railway lines in the Tokyo area.
- The 209th Battalion, CEF was a unit in the Canadian Expeditionary Force during the First World War.