Supriya Ghosh (Editor)

220 (number)

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220
  
221 →

Factorization
  
2× 5 × 11

Binary
  
110111002

Cardinal
  
two hundred twenty

Roman numeral
  
CCXX

Ordinal
  
220th (two hundred and twentieth)

220 (two hundred [and] twenty) is the natural number following 219 and preceding 221.

Contents

In mathematics

It is a composite number, with its divisors being 1, 2, 4, 5, 10, 11, 20, 22, 44, 55 and 110, making it an amicable number with 284. Every number up to 220 may be expressed as a sum of its divisors, making 220 a practical number. Also, being divisible by the sum of its digits, 220 is a Harshad number.

It is the sum of four consecutive primes (47 + 53 + 59 + 61). It is the smallest even number with the property that when represented as a sum of two prime numbers (per Goldbach's conjecture) both of the primes must be greater than or equal to 23. There are exactly 220 different ways of partitioning 64 = 82 into a sum of square numbers.

It is a tetrahedral number, the sum of the first ten triangular numbers, and a dodecahedral number. If all of the diagonals of a regular decagon are drawn, the resulting figure will have exactly 220 regions.

It is the sum of the sums of the divisors of the first 16 positive integers.

In other fields

The number 220 can also refer to:

  • The years 220 AD and 220 BC.
  • A common voltage in many countries.
  • An SMTP code meaning "service ready"
  • A series of garden tractors produced by Case (and later by Case IH) in the 1970s and 1980s - the series included the 220(10HP), the 222(12HP) and the 224(14HP).
  • 220 film, a film format for medium format cameras.
  • A single by music duo t.A.T.u.
  • An album by guitarist Phil Keaggy.
  • The InterCity 225 train, a newer version of the InterCity 125.
  • .220 Russian and .220 Swift, firearm cartridges

    • References

    220 (number) Wikipedia
    (Text) CC BY-SA