260 (number)

260 (two hundred [and] sixty) is the magic constant of the n×n magic square and n-Queens Problem for n = 8, the size of an actual chess board.

Template:Numbers 200s
Cardinal	Two hundred [and] sixty
Ordinal	260th
Factorization	$260=2^{2}\cdot 5\cdot 13$
Roman numeral	CCLX
Binary	100000100
Hexadecimal	104

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.

In other fields

260 is also:

Given a 4 by 4 chessboard, there are only 260 ways to place six non-attacking bishops.
The year AD 260 and 260 BC.
The number of days in a Mayan calendar Tzolkin

Other numbers from 261 to 269

Two hundred [and] sixty-one 261 = 3²·29, nonagonal number, Harshad number

Two hundred [and] sixty-two 262 = 2·131, meandric number, open meandric number, untouchable number

Two hundred [and] sixty-three 263 prime, safe prime, sum of five consecutive primes (43 + 47 + 53 + 59 + 61), balanced prime, Chen prime, Eisenstein prime with no imaginary part, strictly non-palindromic number

Two hundred [and] sixty-four 264 = 2³·3·11, Harshad number

Two hundred [and] sixty-five 265 = 5·53, Padovan number, centered square number, Smith number

Two hundred [and] sixty-six 266 = 2·7·19, sphenic number, Harshad number, nontotient, noncototient, self number, repdigit in base 11 (222).

Two hundred [and] sixty-seven 267 = 3·89

Two hundred [and] sixty-eight 268 = 2²·67, noncototient, untouchable number

Two hundred [and] sixty-nine 269 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