2185
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 2880
- Proper Divisor Sum (Aliquot Sum)
- 695
- 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
- 1584
- Möbius Function
- -1
- Radical
- 2185
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 107
- 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
- Numbers k such that 4!*(2k-5)!/(k!*(k-1)!) is an integer.at n=17A004784
- 5!(2n-6)!/n!(n-1)! is an integer.at n=22A004785
- Second pentagonal numbers: a(n) = n*(3*n + 1)/2.at n=38A005449
- a(n) = 5*a(n-2) - 2*a(n-4), with initial terms 0,1,1,3.at n=12A005824
- Coordination sequence T5 for Zeolite Code MEL.at n=30A008154
- Numbers k such that C(k,3) = C(x,3) + C(y,3) is solvable.at n=47A010330
- M-sequences from multicomplexes on 4 variables with all monomials of degree 4 but none of degree larger than n.at n=6A011812
- a(n) = ((n+1)-st Lucas number) - (n-th non-Lucas number).at n=14A014243
- Numbers k such that phi(k + 11) | sigma(k).at n=44A015831
- Cycle class sequence c(n) (the number of true cycles of length n in which a certain node is included) for zeolite VNI = VPI-9 Rb44K4[Zn24Si96O240].48H2O starting with a T5 atom.at n=11A019258
- Pseudoprimes to base 68.at n=35A020196
- Numbers k such that the continued fraction for sqrt(k) has period 38.at n=17A020377
- Ordered sequence of distinct terms of the form floor(x^i * floor(x^j)), i,j >= 0, where x = sqrt(3).at n=34A022769
- Number of Dyck n-paths with ascents and descents of length equal to 1 (mod 3).at n=15A023432
- Convolution of Fibonacci numbers and A014306.at n=16A023614
- Numbers with exactly 6 2's in their ternary expansion.at n=13A023704
- a(n) = (prime(n)^2 - 1)/24.at n=47A024702
- Numbers n such that n divides the (right) concatenation of all numbers <= n written in base 20 (most significant digit on right).at n=13A029513
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 20 ones.at n=30A031788
- Number of dyslexic rooted planar trees with n nodes where any 2 subtrees extending from the same node are different.at n=12A032066