260 (two hundred [and] sixty) is the natural number following 259 and preceding 261.

← 259 260 261 →
Cardinaltwo hundred sixty
Ordinal260th
(two hundred sixtieth)
Factorization22 × 5 × 13
Greek numeralΣΞ´
Roman numeralCCLX
Binary1000001002
Ternary1001223
Senary11126
Octal4048
Duodecimal19812
Hexadecimal10416

It is also the magic constant of the n×n normal magic square and n-queens problem for n = 8, the size of an actual chess board.

260 is also the magic constant of the Franklin magic square devised by Benjamin Franklin.

52 61 4 13 20 29 36 45
14 3 62 51 46 35 30 19
53 60 5 12 21 28 37 44
11 6 59 54 43 38 27 22
55 58 7 10 23 26 39 42
9 8 57 56 41 40 25 24
50 63 2 15 18 31 34 47
16 1 64 49 48 33 32 17

The minor diagonal gives 260, and in addition a number of combinations of two half diagonals of four numbers from a corner to the center give 260.

There are 260 days in the Mayan sacred calendar Tzolkin.

260 may also refer to the years AD 260 and 260 BC.

Integers from 261 to 269

261

Main article: 261 (number)

261 = 32·29, lucky number, nonagonal number, unique period in base 2, number of possible unfolded tesseract patterns.

262

Main article: 262 (number)

262 = 2·131, meandric number, open meandric number, untouchable number, happy number, palindrome number, semiprime.

263

Main article: 263 (number)

263 is a prime, safe prime, happy number, sum of five consecutive primes (43 + 47 + 53 + 59 + 61), balanced prime, Chen prime, Eisenstein prime with no imaginary part, strictly non-palindromic number, Bernoulli irregular prime, Euler irregular prime, Gaussian prime, full reptend prime, Solinas prime, Ramanujan prime.

264

Main article: 264 (number)

264 = 23·3·11 = number of edges in a 11·11 square grid.[1] The sum of all 2-digit numbers from 264, is 264: 24 + 42 + 26 + 62 + 46 + 64 = 264. 132 and 396 share this property.[2]

264 equals the sum of the squares of the digits of its own square in base 15. This property is shared with 1, 159, 284, 306 and 387.

265

Main article: 265 (number)

265 = 5·53, semiprime, Padovan number, number of derangements of 6 elements, centered square number, Smith number, subfactorial 6.

266

266 = 2·7·19 = , sphenic number, nontotient, noncototient, repdigit in base 11 (222). 266 is also the index of the largest proper subgroups of the sporadic group known as the Janko group J1.

267

Main article: 267 (number)

268

Main article: 268 (number)

269

Main article: 269 (number)

269 is a prime, twin prime with 271, sum of three consecutive primes (83 + 89 + 97), Chen prime, Eisenstein prime with no imaginary part, highly cototient number, strictly non-palindromic number, full reptend prime

References

  1. ^ Sloane, N. J. A. (ed.). "Sequence A046092 (4 times triangular numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  2. ^ Wells, D. The Penguin Dictionary of Curious and Interesting Numbers London: Penguin Group. (1987): 138
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