17840
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 20
- Divisor Sum
- 41664
- Proper Divisor Sum (Aliquot Sum)
- 23824
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7104
- Möbius Function
- 0
- Radical
- 2230
- 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
- yes
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 97
- Smith Number
- yes
- 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
- Numbers k such that sigma(k) = sigma(k+4).at n=22A015863
- Number of subsets of { 1, ..., n } containing an A.P. of length 10.at n=21A018795
- Coefficient triangle of certain polynomials.at n=40A056588
- Fifth column sequence of triangle A056588.at n=4A056591
- Triangle T(n,k) of numbers of minimal 5-covers of an unlabeled n+5-set that cover k points of that set uniquely (k=5,..,n+5).at n=40A057968
- Expansion of (1+t^2+4*t^3+2*t^4+t^5+3*t^6)/((1-t)^2*(1-t^2)*(1-t^3)^2).at n=27A100779
- a(n) = Sum{k=1..n} Fibonacci(floor(n/k)).at n=21A119737
- Unsigned version of A056588.at n=40A126770
- Total Wiener index of double-star trees with n nodes.at n=29A186235
- Number of partitions of n+6 with largest inscribed rectangle having area <= n.at n=30A218627
- Coefficients in asymptotic expansion of sequence A259871.at n=6A260949
- The sum of the necessary diagonal movements from each square unit of an n X n+1 rectangle to reach any of the corners of the rectangle.at n=31A279034
- Number of 6 X n 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.at n=8A281210
- Numbers k such that Bernoulli number B_{k} has denominator 230010.at n=4A295593
- a(n) = 1 + Sum_{k=1..n} Sum_{d|k} mu(k/d)*p(d), where p(d) = number of partitions of d (A000041).at n=28A306912
- Expansion of (1/(1 - x)) * Sum_{k>=0} x^(k*(2*k+1)) / Product_{j=1..2*k} (1 - x^j).at n=51A318155
- Expansion of (1/(1 - x)) * Sum_{k>=1} x^(k*(2*k-1)) / Product_{j=1..2*k-1} (1 - x^j).at n=51A318156
- Number of subsets of {1..n} such that it is possible to choose a different prime factor of each element.at n=21A370582
- a(0)=1; a(n) = sum of all previous terms, eliminating repeated digits (starting from the left).at n=39A370748