View source for 261 (number)

{{Infobox number
| number = 261
| divisor = 1, 3, 9, 29, 87, 261
}}
'''261''' ('''two hundred [and] sixty-one''') is a natural number proceeded by the number [[260 (number)|260]] and followed by [[262 (number)|262]]. It has the prime factorization 3<sup>2</sup>·29.

== Mathematical properties ==
There are six divisors of this number, the divisors being {{num|1}}, {{num|3}}, {{num|9}}, {{num|29}}, {{num|87}}, and 261 itself.<ref>{{Cite news|url=http://numbermatics.com/n/261/|title=Facts about the number 261|work=Numbermatics - the number explorer|access-date=2017-03-20}}</ref> 261 is a [[Deficient number|deficient number]], since {{math|1=1 + 3 + 9 + 29 + 87 = 129 < 261.}}

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

261 is a [[Lucky number|lucky number]], as well as an [[Odious number|odious number]], meaning it has an odd number of 1's in its [[Binary number|binary]] expansion, which is {{math|100000101<sub>2</sub>}} (with 3 ones in it).<ref>{{Cite web|url=http://www.numbergossip.com/261|title=Number Gossip: 261|website=www.numbergossip.com|language=en|access-date=2017-03-20}}</ref>

== References ==
{{reflist}}


[[Category:Integers]]

{{Sourceattribution|261 (number)}}