9075
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 18
- Divisor Sum
- 16492
- Proper Divisor Sum (Aliquot Sum)
- 7417
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4400
- Möbius Function
- 0
- Radical
- 165
- Omega Function (Ω)
- 5
- 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
- 65
- 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
- no
- Odd
- yes
Appears in sequences
- a(n) = n*(n+1)^2*(n+2)^2/12.at n=9A004282
- a(n) = binomial(n,3)*binomial(n-1,3)/4.at n=8A006542
- a(n) = n*(29*n + 1)/2.at n=25A022287
- a(n) = (d(n)-r(n))/2, where d = A026054 and r is the periodic sequence with fundamental period (1,0,0,0).at n=42A026055
- a(n) = Sum_{k=0..floor(n/2)} A026637(n-k, k).at n=19A026647
- a(n) = floor(n/2) * floor((n-1)/2) * floor((n-2)/2) * floor((n-3)/2) * floor((n-4)/2) / 12.at n=23A028725
- Shifts left 2 places under "CHJ" (necklace, identity, labeled) transform.at n=8A032335
- Numbers whose set of base-14 digits is {3,4}.at n=20A032838
- Odd numbers with exactly 5 palindromic prime factors (counted with multiplicity).at n=33A046375
- The sigma(EulerPhi)-perfect numbers, where the set of f-perfect numbers for an arithmetical function f is defined in A066218.at n=4A066226
- Numbers n such that sum of the squares of the prime factors of n equals the sum of the squares of the digits of n.at n=9A067184
- Numbers k such that sigma(k^2+1) is a perfect square.at n=12A067465
- Numbers n such that sopf(phi(n)) = phi(sopf(n)), where sopf(x) = sum of the distinct prime factors of x.at n=27A076531
- 1/6 of the number of ways of 3-coloring a 4 X n grid.at n=4A078100
- 1/6 of the number of ways of 3-coloring an (n-1) X n grid.at n=3A078101
- Triangle read by rows: T(n,k) = number of peakless Motzkin paths of length n having k (1,1) steps (can be easily translated into RNA secondary structure terminology). Except for row 0, row n has ceiling(n/2) entries.at n=60A089732
- Number of connected 2-element antichains on a labeled n-set.at n=9A094033
- Expansion of (1+2x^2)/(1-x-4x^5).at n=20A098524
- Records for terms in the continued fraction of Catalan's constant.at n=9A099789
- Triangle read by rows: T(n,k) = (k+1)(k+2)(n+2)(n+3)(6n^2 - 8n*k + 18n + 3k^2 - 11k + 12)/144 for 0<=k<=n.at n=44A107981