Natural number
Cardinal two hundred forty Ordinal 240th (two hundred fortieth) Factorization 24 × 3 × 5 Divisors 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, 20, 24, 30, 40, 48, 60, 80, 120, 240 Greek numeral ΣΜ´ Roman numeral CCXL ,ccxl Binary 111100002 Ternary 222203 Senary 10406 Octal 3608 Duodecimal 18012 Hexadecimal F016
240 (two hundred [and] forty ) is thenatural number following239 and preceding241 .
240 is apronic number , since it can be expressed as the product of two consecutive integers,15 and16 .[ 1] It is asemiperfect number ,[ 2] equal to the concatenation of two of its proper divisors (24 and 40).[ 3]
It is also the 12thhighly composite number ,[ 4] with 20 divisors in total, more than any smaller number;[ 5] and arefactorable number or tau number, since one of its divisors is 20, which divides 240 evenly.[ 6]
240 is thealiquot sum of only two numbers: 120 and 57121 (or 2392 ); and is part of the12161 -aliquot tree that goes: 120,240 , 504, 1056, 1968, 3240, 7650, 14112, 32571, 27333, 12161, 1, 0.
It is the smallest number that can be expressed as a sum of consecutive primes in three different ways:[ 7] 240 = 113 + 127 240 = 53 + 59 + 61 + 67 240 = 17 + 19 + 23 + 29 + 31 + 37 + 41 + 43 {\displaystyle {\begin{aligned}240&=113+127\\240&=53+59+61+67\\240&=17+19+23+29+31+37+41+43\\\end{aligned}}}
240 ishighly totient , since it has thirty-one totient answers, more than any previous integer.[ 8]
It is palindromic in bases 19 (CC19 ), 23 (AA23 ), 29 (8829 ), 39 (6639 ), 47 (5547 ) and 59 (4459 ), while aHarshad number in bases 2, 3, 4, 5, 6, 7, 9, 10, 11, 13, 14, 15 (and 73 other bases).
240 is thealgebraic polynomial degree of sixteen-cyclelogistic map ,r 16 . {\displaystyle r_{16}.} [ 9] [ 10] [ 11]
240 is the number of distinct solutions of theSoma cube puzzle.[ 12]
There are exactly 240 visible pieces of what would be afour-dimensional version of theRubik's Revenge — a4 × 4 × 4 {\displaystyle 4\times 4\times 4} Rubik's Cube . A Rubik's Revenge in three dimensions has 56 (64 – 8) visible pieces, which means a Rubik's Revenge in four dimensions has 240 (256 – 16) visible pieces.
240 is the number ofelements in the four-dimensional24-cell (or rectified16-cell ): 24cells , 96faces , 96edges , and 24vertices . On the other hand, theomnitruncated 24-cell ,runcinated 24-cell , andruncitruncated 24-cell all have 240 cells, while therectified 24-cell andtruncated 24-cell have 240 faces. Theruncinated 5-cell ,bitruncated 5-cell , andomnitruncated 5-cell (the latter with 240 edges) all sharepentachoric symmetry [ 5 , 3 , 2 ] {\displaystyle [5,3,2]} , oforder 240; four-dimensionalicosahedral prisms withWeyl group H 3 × A 1 {\displaystyle \mathrm {H_{3}} \times \mathrm {A_{1}} } also have order 240. Therectified tesseract has 240 elements as well (24 cells, 88 faces, 96 edges, and 32 vertices).
In five dimensions, therectified 5-orthoplex has 240 cells and edges, while thetruncated 5-orthoplex andcantellated 5-orthoplex respectively have 240 cells and vertices. Theuniform prismatic familyA 1 × A 4 {\displaystyle \mathrm {A_{1}} \times \mathrm {A_{4}} } is of order 240, where its largest member, theomnitruncated 5-cell prism , contains 240 edges. In the still five-dimensionalH 4 × A 1 {\displaystyle \mathrm {H_{4}} \times \mathrm {A_{1}} } prismatic group, the600-cell prism contains 240 vertices. Meanwhile, in six dimensions, the6-orthoplex has 240tetrahedral cells , where the6-cube contains 240squares as faces (and abirectified 6-cube 240 vertices), with the6-demicube having 240 edges.
E 8 in eight dimensions has 240roots .
^ Sloane, N. J. A. (ed.)."Sequence A002378 (Oblong (or promic, pronic, or heteromecic) numbers)" .TheOn-Line Encyclopedia of Integer Sequences . OEIS Foundation. Retrieved2016-05-30 .^ "Sloane's A005835 : Pseudoperfect (or semiperfect) numbers" .The On-Line Encyclopedia of Integer Sequences . OEIS Foundation. Retrieved2016-09-05 .^ "Sloane's A050480 : Numbers that can be written as a concatenation of distinct proper divisors" .The On-Line Encyclopedia of Integer Sequences . OEIS Foundation. Retrieved2016-09-05 .^ "A002182 - OEIS" .oeis.org . Retrieved2024-11-28 .^ "Sloane's A002182 : Highly composite numbers" .The On-Line Encyclopedia of Integer Sequences . OEIS Foundation. Retrieved2016-05-31 .^ Sloane, N. J. A. (ed.)."Sequence A033950 (Refactorable numbers)" .TheOn-Line Encyclopedia of Integer Sequences . OEIS Foundation. Retrieved2016-04-18 .^ "Sloane's A067373 : Integers expressible as the sum of (at least two) consecutive primes in at least 3 ways" .The On-Line Encyclopedia of Integer Sequences . OEIS Foundation. 2009-08-15. Retrieved2021-08-27 .^ "Sloane's A097942 : Highly totient numbers" .The On-Line Encyclopedia of Integer Sequences . OEIS Foundation. Retrieved2016-05-28 .^ Bailey, D. H.; Borwein, J. M.; Kapoor, V.; Weisstein, E. W. (2006)."Ten Problems in Experimental Mathematics" (PDF) .American Mathematical Monthly .113 (6).Taylor & Francis :482– 485.doi :10.2307/27641975 .JSTOR 27641975 .MR 2231135 .S2CID 13560576 .Zbl 1153.65301 . ^ Sloane, N. J. A. (ed.)."Sequence A091517 (Decimal expansion of the value of r corresponding to the onset of the period 16-cycle in the logistic map.)" .TheOn-Line Encyclopedia of Integer Sequences . OEIS Foundation. Retrieved2024-02-29 .^ Sloane, N. J. A. (ed.)."Sequence A118454 (Algebraic degree of the onset of the logistic map n-bifurcation.)" .TheOn-Line Encyclopedia of Integer Sequences . OEIS Foundation. Retrieved2024-02-29 .^ Weisstein, Eric W."Soma Cube" .Wolfram MathWorld . Retrieved2016-09-05 .
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