15440
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 20
- Divisor Sum
- 36084
- Proper Divisor Sum (Aliquot Sum)
- 20644
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6144
- Möbius Function
- 0
- Radical
- 1930
- Omega Function (Ω)
- 6
- Little Omega Function (ω)
- 3
Special
- Factorial
- no
- Catalan Number
- no
- Bell Number
- no
- Motzkin Number
- no
- Primorial
- no
Figurate Numbers
- Fibonacci Number
- no
- Triangular Number
- no
- Perfect Square
- no
- Perfect Cube
- no
- Pentagonal Number
- no
- Hexagonal Number
- no
- Lucas Number
- no
- Tetrahedral Number
- no
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- no
Recreational
- Happy Number
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 27
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- Prime Power
- no
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- yes
- Odd
- no
Appears in sequences
- -log(cos(arctanh(x)))=1/2!*x^2+10/4!*x^4+280/6!*x^6+15440/8!*x^8...at n=3A012243
- Number of partitions satisfying cn(0,5) + cn(1,5) + cn(4,5) <= cn(2,5) + cn(3,5).at n=40A039878
- Numbers k such that 3*2^k + 5 is prime.at n=49A057913
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, 0, 1), (-1, 1, 1), (0, 0, 1), (0, 1, -1), (1, -1, 0)}.at n=10A148170
- Number of (n+2)X(5+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000001 00000011 or 00001111.at n=5A260367
- Number of (n+2)X(6+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000001 00000011 or 00001111.at n=4A260368
- G.f.: 1/((1-t^11)^2*(1-t)*(1-t^3)*(1-t^5)*(1-t^7)*(1-t^9)*(1-t^13)*(1-t^15)*(1-t^17)*(1-t^19)*(1-t^21)).at n=63A266751
- a(n) is n times the minimum moment of inertia of an n-celled polyomino about an axis through the center of mass perpendicular to the plane of the polyomino, with a unit point mass in the center of each of the cells.at n=45A365964
- Number of subsets of {1..n} such that only one set can be obtained by choosing a different prime factor of each element.at n=21A370584
- a(n) is the smallest number which can be represented as the sum of 4 distinct nonzero tetrahedral numbers in exactly n ways, or -1 if no such number exists.at n=18A374809
- G.f. satisfies A(x) = -(A(x^3) + A(x^4)) / A(-x^2).at n=45A385915