17895
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 30
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 28656
- Proper Divisor Sum (Aliquot Sum)
- 10761
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 9536
- Möbius Function
- -1
- Radical
- 17895
- Omega Function (Ω)
- 3
- 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
- 123
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- yes
- 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
- Dirichlet convolution of d(n) (number of divisors) with Fibonacci numbers.at n=21A034772
- Number of upward triangles in a Star of David matchstick arrangement of size n.at n=15A045950
- Numbers k such that k | 5^k + 4^k + 3^k + 2^k + 1^k.at n=42A056741
- a(n) = Sum_{k=1..n} binomial(k, n mod k).at n=20A072951
- Triangle read by rows: T(n,k) is the number of k-matchings of the corona L'(n) of the ladder graph L(n)=P_2 X P_n. and the complete graph K(1); in other words, L'(n) is the graph constructed from L(n) by adding for each vertex v a new vertex v' and the edge vv'.at n=42A102435
- a(n) = (4*n^3-3*n^2+5*n-3)/3.at n=23A177342
- Triangle of coefficients of polynomials u(n,x) jointly generated with A209140; see the Formula section.at n=50A209139
- E.g.f. A(x) satisfies: A'(x) = exp(A(A(x))).at n=6A214645
- Number of (n+2)X(n+2) 0..4 arrays with every consecutive three elements in every row and column not having exactly two distinct values, and in every diagonal and antidiagonal having exactly two distinct values, and new values 0 upwards introduced in row major order.at n=6A252803
- Number of (n+2)X(7+2) 0..4 arrays with every consecutive three elements in every row and column not having exactly two distinct values, and in every diagonal and antidiagonal having exactly two distinct values, and new values 0 upwards introduced in row major order.at n=6A252810
- Positions of 3's in A264977; positions of 6's in A277330.at n=36A277713
- Number of prime parts in the partitions of n into 9 parts.at n=41A309438
- a(n) is the row of the Trithoff (tribonacci) array that contains the tails of the sequence which is n times the tribonacci numbers.at n=22A351685