8138
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 13188
- Proper Divisor Sum (Aliquot Sum)
- 5050
- 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
- 3744
- Möbius Function
- -1
- Radical
- 8138
- Omega Function (Ω)
- 3
- 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
- 158
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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
- T(n,n-3), array T as in A047089.at n=7A047094
- Number of collinear triples in a 3 X n rectangular grid.at n=26A057566
- Numbers beginning and ending with their multiplicative digital root.at n=43A064704
- Main diagonal of A101866.at n=46A101867
- Numbers n such that P(4n) is prime, where P(m) is the number of partitions of m.at n=29A111045
- Multiples of 13 containing a 13 in their decimal representation.at n=22A121033
- Expansion of g.f.: Product_{k>=1} 1+k*x^k/(1-x^k)^2.at n=14A163318
- Triangle read by rows: T(n,0) = (n+1)^2, T(n,k) = T(n,k-1) + T(n-1,k) for 0 < k < n, and T(n,n) = T(n,n-1).at n=41A165996
- Row sums of triangle A179943.at n=8A179944
- Triangle of coefficients of polynomials v(n,x) jointly generated with A210603; see the Formula section.at n=40A210738
- Starting from a(1)=1, a(n) is the minimum integer greater than a(n-1) such that a(n)+a(n-1), a(n)*a(n-1)+1 and a(n)*a(n-1)-1 are all primes.at n=41A228590
- Solutions to phi(n) = phi(sigma(n)) that are not given by Theorem 3 of Golomb's manuscript.at n=48A260021
- Expansion of x * psi(x^3) * psi(x^12) / f(-x) in powers of x where psi(), f() are Ramanujan theta functions.at n=30A260600
- The least common multiple of 1+n and 1+n^2.at n=25A281660
- Sequence lists numbers k > 1 such that k^3 == d(k) (mod sigma(k)), where d = A000005 and sigma = A000203.at n=6A323250
- a(n) = n*(2*(n - 2)*n + (-1)^n + 3)/4.at n=26A323724
- Triangular array read by rows: row n shows the coefficients of the polynomial p(x,n) constructed as in Comments; these polynomials form a strong divisibility sequence.at n=28A327322
- Expansion of Product_{k>=1} B(x^k), where B(x) is the g.f. of A111374.at n=45A327851
- a(n) = p(0,n), where p(x,n) is the strong divisibility sequence of polynomials based on sqrt(5) as in A327322.at n=7A329011
- Difference between upper and lower member of a pair of adjacent perfect powers A340700 and A340701, both with exponents > 2.at n=17A340706