9108
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 36
- Divisor Sum
- 26208
- Proper Divisor Sum (Aliquot Sum)
- 17100
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 2640
- Möbius Function
- 0
- Radical
- 1518
- Omega Function (Ω)
- 6
- Little Omega Function (ω)
- 4
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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 60
- 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
- Heptagonal (or 7-gonal) pyramidal numbers: a(n) = n*(n+1)*(5*n-2)/6.at n=22A002413
- Expansion of (2 - x)^4/(1 - x)^8.at n=6A006637
- Number of equilateral triangles formed by triples of points taken from a hexagonal chunk of side n in the hexagonal lattice.at n=8A008893
- Let j = | i - i_written_backwards |, k = j + j_written_backwards; then k is in this sequence.at n=40A008920
- a(n) = floor( n*(n-1)*(n-2)/10 ).at n=46A011892
- a(n) = floor( n*(n-1)*(n-2)*(n-3)/28 ).at n=24A011938
- a(n) is least k such that k and 9k are anagrams in base n (written in base 10).at n=37A023101
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (1, p(1), p(2), ...), t = (composite numbers).at n=29A025100
- Sums of 3 distinct powers of 6.at n=18A038479
- Composite numbers divisible by the palindromic sum of their prime factors (counted with multiplicity).at n=21A046358
- Number of nonempty subsets of {1,2,...,n} in which exactly 2/3 of the elements are <= (n-2)/2.at n=18A047184
- Partial sums of A051879.at n=7A050405
- Number of multigraphs with loops on 3 nodes with n edges.at n=20A050531
- Lesser members of g-reduced amicable pairs a < b such that sigma(a) = sigma(b) = a + b + gcd(a,b).at n=36A054573
- a(n) = binomial(n,4) + binomial(n,2).at n=22A055795
- Numbers k such that k^128 + 1 is prime.at n=22A056994
- Numerators of the convergents to the continued fraction of Pi^2/6.at n=9A080016
- a(n) = 7*n^2 + n.at n=36A092277
- Triangle read by rows: T(n,k) is the number of binary trees with n edges and such that the first leaf in the preorder traversal is at level k (1<=k<=n). A binary tree is a rooted tree in which each vertex has at most two children and each child of a vertex is designated as its left or right child.at n=48A120988
- Numbers k such that if you subtract k-reversed from k you get a natural number with the same digits as k.at n=6A121969