16980
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 24
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 47712
- Proper Divisor Sum (Aliquot Sum)
- 30732
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4512
- Möbius Function
- 0
- Radical
- 8490
- Omega Function (Ω)
- 5
- 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
- 128
- 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
- yes
- Odd
- no
Appears in sequences
- a(n) is the number of c-nets with n+1 vertices and 2n edges, n >= 1.at n=7A001506
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (-1, 1, 0), (0, 0, -1), (0, 0, 1), (1, 0, -1)}.at n=10A148557
- Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of 2 n steps taken from {(-1, 0), (-1, 1), (1, -1), (1, 1)}.at n=5A151402
- Number of ways to place zero or more nonadjacent 0,0 1,0 1,1 2,1 3,1 3,2 4,1 4,3 polyhexes in any orientation on a planar nXnXn triangular grid.at n=8A155369
- a(n) = 1000*n - 20.at n=16A157515
- Triangle read by rows: T(n,k) is the number of c-nets with n+1 faces and k+1 vertices, 1 <= k <= n. But see A290326 for a better version.at n=35A210252
- a(n) = n * A000699(n).at n=5A212273
- Number of distinct topologies on an n-set that have exactly 11 open sets.at n=6A281779
- Triangle read by rows: T(n,k) is the number of c-nets with n+1 faces and k+1 vertices.at n=45A290326
- Exponential convolution of partition numbers (A000041) with themselves.at n=9A307755
- Number of maximal subsets of {1..n} such that every orderless pair of distinct elements has a different sum.at n=24A325878
- Midpoints k of a pair of twin primes such that sigma(k) is also the midpoint of a pair of twin primes.at n=27A349981
- Number of integer partitions of n where the least part is the unique mode.at n=39A364193