6678
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 27
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 16848
- Proper Divisor Sum (Aliquot Sum)
- 10170
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 1872
- Möbius Function
- 0
- Radical
- 2226
- 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
- 93
- 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
- Number of permutations of length n with 5 consecutive ascending pairs.at n=9A001261
- Triangle read by rows: T(n,k) is the number of permutations of [n] having k consecutive ascending pairs (0 <= k <= n-1).at n=49A010027
- Number of inequivalent ways (mod D_4) a pair of checkers can be placed on an n X n board.at n=17A014409
- a(n) = n*(17*n + 1)/2.at n=28A022275
- Numbers k such that 159*2^k + 1 is prime.at n=27A032456
- Base 5 digits are, in order, the first n terms of the periodic sequence with initial period 2,0,3.at n=5A037619
- Triangle giving number of unbranched catapolytetragons, read by rows.at n=60A038766
- Numbers whose base-9 representation has exactly 5 runs.at n=24A043634
- Number of homeomorphically irreducible multigraphs (or series-reduced multigraphs or multigraphs without nodes of degree 2) on 7 labeled nodes.at n=5A060537
- For even n>=4, let f(n)=A066285(n/2) be the minimal difference between primes p and q whose sum is n. This sequence contains the successive maxima of f.at n=52A066286
- Number of graphical partitions of simple Eulerian graphs (partitions given by the degrees of vertices of simple (no loops or multiple edges) graphs having only vertices of even degrees) having n edges.at n=42A069831
- a(1)=1, a(n) is the smallest integer > a(n-1) such that the largest element in the simple continued fraction for S(n)=1/a(1)+1/a(2)+...+1/a(n) equals n^2.at n=16A070902
- Number of parallelogram polyominoes of site-perimeter n (also called staircase polyominoes, although that term is overused).at n=16A075125
- Balanced numbers k such that 2*k is not a balanced number (k is in A020492, 2*k is not).at n=46A076484
- Sum of primes between successive pairs of twin primes.at n=39A078731
- Where records occur in A079366.at n=10A079368
- Square root of coefficients of power series: A083352(x)^2 + A083352(x) - 1; term-by-term square root of A083353.at n=79A083354
- a(n) = (n+1)(n+2)^3*(n+3)(n+4)(5n^2 + 16n + 15)/1440.at n=4A108670
- Triangle read by rows: T(n,k) is the number of permutations of [n] having k small descents (n >= 1; 0 <= k <= n-1). A small descent in a permutation (x_1,x_2,...,x_n) is a position i such that x_i - x_(i+1) = 1.at n=50A123513
- Composite numbers such that the square mean of their prime factors is a nonprime integer (where the prime factors are taken with multiplicity and the square mean of c and d is sqrt((c^2+d^2)/2)).at n=20A134602