17181
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 26208
- Proper Divisor Sum (Aliquot Sum)
- 9027
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 10824
- Möbius Function
- 0
- Radical
- 5727
- Omega Function (Ω)
- 4
- 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
- 79
- 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
- Numbers whose base-7 representation has exactly 6 runs.at n=21A043621
- Numbers whose base-5 representation contains exactly three 1's and three 2's.at n=29A045232
- Numbers n such that n and prime(n) end with the same three digits.at n=13A067841
- Least multiple of 2n-1 ending in prime(n), 0 if no such number exists.at n=41A114780
- Sum of parts, counted without multiplicities, in all partitions of n into odd parts.at n=36A116930
- Sum of cubes of trinomial coefficients: a(n) = Sum_{k=0..2n} trinomial(n,k)^3 where trinomial(n,k) = [x^k] (1 + x + x^2)^n.at n=4A132303
- a(n) is the ratio of the sum of the bends (curvatures) of the circles in the n-th generation of an Apollonian packing to the sum of the bends in the initial four-circle configuration.at n=5A135849
- Multiples of 23 whose digit reversal - 1 is also a multiple of 23.at n=30A166400
- Put the natural numbers together without spaces and read them five at a time advancing one space each time.at n=23A193493
- Number of partitions of n, where the difference between the number of odd parts and the number of even parts is 4.at n=48A240013
- T(n,k)=Number of nXk arrays of permutations of 0..n*k-1 with rows nondecreasing modulo 4 and columns nondecreasing modulo 7.at n=23A264831
- Number of 3 X n arrays of permutations of 0..n*3-1 with rows nondecreasing modulo 4 and columns nondecreasing modulo 7.at n=4A264833
- G.f.: Product_{m>0} (1 + x^m + 2*x^(2*m) + 3*x^(3*m)).at n=32A290269
- Number of compositions of n with equal differences up to sign.at n=45A325557
- Number of distinct circles that can be constructed from an n x n square grid of points using only a compass.at n=13A359931
- Numbers k that divide the k-th central Delannoy number.at n=29A372901
- Numbers k that divide the k-th Apéry number (A005258).at n=19A372943