8380
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 17640
- Proper Divisor Sum (Aliquot Sum)
- 9260
- 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
- 3344
- Möbius Function
- 0
- Radical
- 4190
- Omega Function (Ω)
- 4
- 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
- 109
- 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(1) = 7; a(n+1) = a(n)-th nonprime, where nonprimes begin at 0.at n=32A025002
- Numerators of continued fraction convergents to sqrt(551).at n=5A042054
- Number of 3-antichain covers of a labeled n-set.at n=6A056046
- Triangle read by rows: T(n,k) is the number of labeled monoids of order n with k idempotents.at n=13A058157
- Number of ways to cover (without overlapping) a ring lattice (necklace) of n sites with molecules that are 6 sites wide.at n=35A058367
- Composite numbers m such that phi(m)*sigma(m) is divisible by m-1.at n=20A065149
- Diagonal in array of n-gonal numbers A081422.at n=19A081437
- Triangle read by rows, in which n-th row contains smallest set of n consecutive numbers with distinct prime signatures.at n=50A083788
- Number of pairs with two different elements which can be obtained by selecting unique elements from two sets with n+1 and n^2 elements respectively and n common elements.at n=20A085490
- Partial sums of Chebyshev sequence S(n,20)= U(n,10)=A075843(n+1).at n=3A097833
- a(1) = a(2) = 1, a(n) = a(n-1) + A007947(a(n-2)) for n >= 3, i.e., a(n) = a(n-1) plus the largest squarefree divisor of a(n-2).at n=23A121367
- Row sums of number triangle A124816.at n=13A124818
- Triangle T(n,k), 0 <= k <= n, read by rows given by: T(0,0)=1, T(n,k)=0 if k < 0 or if k > n, T(n,0) = 3*T(n-1,0) + T(n-1,1), T(n,k) = T(n-1,k-1) + T(n-1,k) + T(n-1,k+1) for k >= 1.at n=37A126954
- Binomial transform of [1, 3, 7, 0, 0, 0, ...].at n=49A140063
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (-1, 0, 0), (0, 0, 1), (1, 0, 1), (1, 1, -1)}.at n=7A150550
- a(n) = 289*n - 1.at n=28A158253
- a(n) = 441*n + 1.at n=18A158322
- E.g.f. A(x) satisfies: x*A(x) equals column 0 in the matrix log of the Riordan array (A(x), x*A(x)).at n=5A179421
- Diagonal sums of number triangle A184879.at n=17A184880
- Number of 3X2 integer matrices with each row summing to zero, row elements in nondecreasing order, rows in lexicographically nondecreasing order, and the sum of squares of the elements <= 2*n^2 (number of collections of 3 zero-sum 2-vectors with total modulus squared not more than 2*n^2, ignoring vector and component permutations).at n=43A192701