8422
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
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 12636
- Proper Divisor Sum (Aliquot Sum)
- 4214
- 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
- 4210
- Möbius Function
- 1
- Radical
- 8422
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 127
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- yes
- Odd
- no
Appears in sequences
- Numbers k such that the continued fraction for sqrt(k) has period 86.at n=21A020425
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 90.at n=21A031588
- E.g.f.: exp(x*exp(x) + 1/2*x^2*exp(x)^2 + 1/4*x^4*exp(x)^4).at n=6A060907
- a(n) = floor(e*(n+3)!) - (n+3)*(n+2)*(n+1)*n*floor(e*(n-1)!).at n=17A080770
- a(n) is the number of distinct n-th powers of functions {1, 2, 3, 4, 5, 6} -> {1, 2, 3, 4, 5, 6}.at n=15A103950
- Slowest increasing and self-describing sequence: first 2 digits are prime digits, followed by 3 composite digits, then 4 prime digits, then 6 composite digits, then 8 prime, then 2 composite, then 2 prime, etc.at n=32A105808
- A sequence related to M-partitions.at n=52A117117
- Triangle of 2-Eulerian numbers.at n=24A144696
- Number of nodes at n-th level in tree in which top node is 1; each node k has children labeled 1, 2, ..., (k+1)^2 at next level.at n=3A147780
- Number of planar n X n X n binary triangular grids symmetric both under 120 degree rotation and reflection with no more than 7 ones in any 4 X 4 X 4 subtriangle.at n=11A153955
- Number of permutations of 1..n with the sum of squared adjacent differences < n*(n-1)/2.at n=8A180069
- a(n) = n^3 - 2*n^2 + 2*n + 1.at n=20A188947
- Sum of the even-indexed parts of all partitions of n.at n=21A207382
- Number of endofunctions f on [n] such that f^9(i) = f(i) for all i in [n].at n=6A245505
- Numbers n such that n!3 + 3 is prime, where n!3 = n!!! is a triple factorial number (A007661).at n=35A249400
- Molien series for invariants of finite Coxeter group D_10 (bisected).at n=33A266773
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 86", based on the 5-celled von Neumann neighborhood.at n=32A270127
- Least integer k such that prime(k+1) - prime(k) = 2 and prime(k+2) - prime(k+1) = 2n, or 0 if no such k exists.at n=23A280941
- Number of ways to write n as an ordered sum of 6 prime power palindromes (A084092).at n=21A282845
- Number of necklace compositions of n such that every restriction to a circular subinterval has a different sum.at n=43A325681