261 (number)

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← 260 261 262 →
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
Quaternary 100114
Quinary 20215
Senary 11136
Octal 4058
Duodecimal 19912
Hexadecimal 10516
Vigesimal D120
Base 36 7936

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

Mathematical properties[edit]

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 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]

In other fields[edit]

261 may refer to...

The years 261 AD or 261 BC.

The steam locomotive Milwaukee Road 261.

References[edit]

  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.