Английская Википедия:220 (number)

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

In mathematics

It is a composite number, with its proper divisors being 1, 2, 4, 5, 10, 11, 20, 22, 44, 55 and 110, making it an amicable number with 284.[1][2] Every number up to 220 may be expressed as a sum of its divisors, making 220 a practical number.[3]

It is the sum of four consecutive primes (47 + 53 + 59 + 61).[4] 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.[5] There are exactly 220 different ways of partitioning 64 = 82 into a sum of square numbers.[6]

It is a tetrahedral number, the sum of the first ten triangular numbers,[7] and a dodecahedral number.[8] If all of the diagonals of a regular decagon are drawn, the resulting figure will have exactly 220 regions.[9]

It is the sum of the sums of the divisors of the first 16 positive integers.[10]

Integers between 221 and 229

221

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222

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223

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224

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225

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226

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227

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228

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229

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Notes

References

Шаблон:Integers