261 (number)

← 260 261 262 →
← 260 261 262 263 264 265 266 267 268 269 → List of numbers; Integers; ← 0 100 200 300 400 500 600 700 800 900 →
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
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. 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

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