261 (number)

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Cardinal two hundred sixty-one
Ordinal 261st
(two hundred sixty-first)
Factorization 32 × 29
Divisors 1, 3, 9, 29, 87, 261
Greek numeral ΣΞΑ´
Roman numeral CCLXI, cclxi
Binary 1000001012
Ternary 1002003
Senary 11136
Octal 4058
Duodecimal 19912
Hexadecimal 10516

261 (two hundred [and] sixty-one) is the natural number following 260 and preceding 262.

In Mathematics

There are six divisors of this number, the divisors being 1, 3, 9, 29, 87, and 261 itself. [1] 261 is a deficient number, since 1 + 3 + 9 + 29 + 87 = 129 < 261.

261 is nonagonal number, [2] unique period in base 2, and the number of possible unfolded tesseract patterns.

261 is a lucky number, [3] as well as an odious number, meaning it has an odd number of 1's in its binary expansion, which is 1000001012 (with 3 ones in it). [4]

References

  1. ↑ "Facts about the number 261". Numbermatics - the number explorer. Retrieved 2017-03-20.
  2. ↑ Sloane, N. J. A. (ed.). "SequenceA001106(nonagonal number)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
  3. ↑ Sloane, N. J. A. (ed.). "SequenceA000959(lucky number)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
  4. ↑ "Number Gossip: 261". www.numbergossip.com. Retrieved 2017-03-20.
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