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← 260 261 262 →
Cardinaltwo hundred sixty-one
Ordinal261st
(two hundred sixty-first)
Factorization32 × 29
Divisors1, 3, 9, 29, 87, 261
Greek numeralΣΞΑ´
Roman numeralCCLXI
Binary1000001012
Ternary1002003
Senary11136
Octal4058
Duodecimal19912
Hexadecimal10516

261 (two hundred [and] sixty-one) is the natural number following 260 and preceding 262. It has the prime factorization 32·29.

Mathematical properties

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, unique period in base 2, and the number of possible unfolded tesseract patterns.

261 is a lucky number, 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). [2]

References

  1. ^ "Facts about the number 261". Numbermatics - the number explorer. Retrieved 2017-03-20.
  2. ^ "Number Gossip: 261". www.numbergossip.com. Retrieved 2017-03-20.