8661
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 11552
- Proper Divisor Sum (Aliquot Sum)
- 2891
- 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
- 5772
- Möbius Function
- 1
- Radical
- 8661
- 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
- 47
- 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
- no
- Odd
- yes
Appears in sequences
- 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 62.at n=21A031560
- Exactly 5 digits from {1,2,3,4,5,6,7,8,9} can precede a(n) to form a lucky number.at n=30A032701
- Number of partitions of n such that cn(0,5) = cn(2,5) <= cn(3,5) = cn(4,5) <= cn(1,5).at n=57A036846
- Numerators of continued fraction convergents to sqrt(950).at n=10A042838
- Expansion of (1+x^3)/((1-x)^3*(1-x^2)^3*(1-x^3)).at n=16A107351
- a(n) = a(n-1) + a(n-3) + a(n-4) + a(n-5) + a(n-7).at n=19A107480
- Trajectory of 4 under map k -> A094077(k).at n=51A117149
- Number of disconnected 2-regular simple graphs on n vertices with girth at least 5.at n=65A185225
- Monotonic ordering of set S generated by these rules: if x and y are in S then (x+1)(y+1) is in S, and 2 is in S.at n=31A192518
- Number of -n..n circular arrays x(0..4) of 5 elements with zero sums of x(i) and x(i)*x((i+1) mod 5).at n=42A202007
- Row sums a(n) of triangle A213936: number of representative necklaces with n beads (C_N symmetry) corresponding to all color signatures given by the partitions [1^n], [2,1^(n-2)], ..., [n-1,1], [n].at n=7A213937
- Numbers n such that Q(sqrt(n)) has class number 7.at n=26A218039
- Fundamental discriminants of real quadratic number fields with class number 7.at n=13A218157
- Number of idempotent 3 X 3 0..n matrices of rank 2.at n=36A224334
- Numbers that end in (..., 128, 128, 128, ...) under the rule: next term = product of the last four digits in the sequence so far.at n=38A240967
- E.g.f.: exp(x*G(x)) where G(x) = 1 + x*G(x)^3 is the g.f. of A001764.at n=5A251569
- Number of (n+1)X(2+1) 0..1 arrays with each row and column prime, read as a binary number with top and left being the most significant bits.at n=8A261755
- T(n,k)=Number of (n+1)X(k+1) 0..1 arrays with each row and column prime, read as a binary number with top and left being the most significant bits.at n=46A261761
- T(n,k)=Number of (n+1)X(k+1) 0..1 arrays with each row and column prime, read as a binary number with top and left being the most significant bits.at n=53A261761
- Row 5 of A277710: Positions of 5's in A264977; positions of 10's in A277330.at n=24A277715