16840
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 37980
- Proper Divisor Sum (Aliquot Sum)
- 21140
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6720
- Möbius Function
- 0
- Radical
- 4210
- Omega Function (Ω)
- 5
- 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
- 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) = 1^n + 2^n + 7^n.at n=5A074503
- Sum of the first 2n+1 primes.at n=42A109723
- Triangle read by rows: A001263 * A128064 * A000012 as infinite lower triangular matrices.at n=46A136536
- Sum of primes < n^2.at n=21A139562
- Consider the base-6 Kaprekar map n->K(n) defined in A165051. Sequence gives numbers belonging to cycles, including fixed points.at n=11A165056
- Consider the base-6 Kaprekar map n->K(n) defined in A165051. Sequence gives numbers belonging to cycles of length greater than 1.at n=8A165058
- Consider the base-6 Kaprekar map n->K(n) defined in A165051. Sequence gives least elements of each cycle, including fixed points.at n=5A165060
- Consider the base-6 Kaprekar map n->K(n) defined in A165051. Sequence gives least elements of each cycle of length > 1.at n=2A165062
- Consider the base-6 Kaprekar map x->K(x) described in A165051. Sequence gives the smallest number that belongs to a cycle of length n under repeated iteration of this map, or -1 if there is no cycle of length n.at n=2A165067
- Smallest member of cycle corresponding to n-th term of A165068.at n=5A165069
- A symmetric triangle, with sum the large Schröder numbers.at n=40A175124
- Composite numbers k such that k = (product of divisors of k) mod (sum of divisors of k).at n=40A187712
- Triangle T(n,k) of numbers/2 of non-extendable (complete) non-self-adjacent simple paths within a square lattice bounded by rectangles with nodal dimensions n and k, n >= k >= 2.at n=13A213106
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 625", based on the 5-celled von Neumann neighborhood.at n=24A273272
- Sum of 5th powers of proper divisors of n.at n=13A279364
- a(n) is the number of semi-meanders with n top arches that have both an arch of length 1 adjacent to the center of the top arch configuration and an arch of length 1 starting or ending the top arch configuration.at n=11A337581
- The sum S of the maximum number of consecutive primes starting with 2 such that S <= prime(n)^2.at n=31A346134
- Number of regions formed in a square by straight line segments when connecting the n-1 points between each corner that divide each edge into n equal parts to the n-1 points on the edge on the opposite side of the square.at n=11A355798
- Expansion of (1/x) * Series_Reversion( x * ((1-x)^3 + x^2) ).at n=6A371434