16005
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 28224
- Proper Divisor Sum (Aliquot Sum)
- 12219
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7680
- Möbius Function
- 1
- Radical
- 16005
- Omega Function (Ω)
- 4
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 45
- 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
- Augmented amicable pairs (larger member of each pair).at n=1A015630
- Cycle class sequence c(n) (the number of true cycles of length n in which a certain node is included) for zeolite MEI = ZSM-18 Nan[AlnSi34-nO68].28H2O (n=2.1-5.7) starting with a T1 atom.at n=13A019145
- a(n) = s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n+1-k), where k = [ (n+1)/2 ], s = A000201 (lower Wythoff sequence).at n=40A024685
- Denominators of continued fraction convergents to sqrt(864).at n=11A042669
- a(n) = n^3+n for odd n, (n^3+n)*3/2 for even n: Row sums of A093915.at n=21A093917
- Triangle read by rows: T(n,k) is the number of k-matchings of the corona K'(n) of the complete graph K(n) and the complete graph K(1); in other words, K'(n) is the graph constructed from K(n) by adding for each vertex v a new vertex v' and the edge vv'.at n=69A100862
- Triangle read by rows: T(n,k) is the number of k-matchings of the corona K'(n) of the complete graph K(n) and the complete graph K(1); in other words, K'(n) is the graph constructed from K(n) by adding for each vertex v a new vertex v' and the edge vv'.at n=74A100862
- Row sums of A126277 = binomial transform of (1, 2, 2, 3, 4, 4, 4, ...)at n=12A124671
- Numbers whose square can be expressed as a+b*c, with a,b,c in geometric sequence.at n=12A130733
- Numbers Y such that 273*Y^2+91 is a square.at n=1A145526
- 5 times octagonal numbers: a(n) = 5*n*(3*n-2).at n=33A153795
- Number of length n+4 0..6 arrays with every five consecutive terms having four times some element equal to the sum of the remaining four.at n=9A249654
- Variation on betrothed numbers.at n=3A281265
- a(n) = U_{n}(n)/(n+1) where U_{n}(x) is a Chebyshev polynomial of the second kind.at n=5A318192
- Positions of 2 in A309059.at n=11A330160
- G.f. satisfies A(x) = 1/(1-x)^2 + x^2*A(x)^4.at n=8A364622
- a(n) = binomial(n,3) + 6*binomial(n,4) + 15*binomial(n,5) + 15*binomial(n,6).at n=11A382081
- Numbers k divisible by A004719(k), excluding trivial cases.at n=33A386501