7880
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 23
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 17820
- Proper Divisor Sum (Aliquot Sum)
- 9940
- 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
- 3136
- Möbius Function
- 0
- Radical
- 1970
- Omega Function (Ω)
- 5
- 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
- 26
- 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(n) is the solution to the postage stamp problem with 4 denominations and n stamps.at n=25A001209
- Mixed partitions of n.at n=31A002096
- Pisot sequence E(5,17), a(n) = floor(a(n-1)^2 / a(n-2) + 1/2).at n=6A010914
- a(n) = (d(n)-r(n))/5, where d = A026040 and r is the periodic sequence with fundamental period (4,0,4,3,4).at n=46A026042
- 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 43.at n=31A031541
- Number of self-avoiding walks of length n from origin in strip Z X {0,1}.at n=16A038577
- a(n) = Sum_{i=0..n} T(i,n-i), array T as in A049735.at n=15A049736
- a(1)=11, If a(n-1)=abcde..., where a,b,c,d,e... are the digits, then a(n)=abcde...+a*bcde...+ab*cde...+abc*de...+abcd*e...+....at n=16A108722
- a(n) = if n mod 2 = 0 then 8*F(n)-n otherwise 8*F(n)-4, where F() = Fibonacci numbers A000045.at n=16A110935
- Number of base 20 circular n-digit numbers with adjacent digits differing by 4 or less.at n=4A125357
- A tabular sequence of arrays counting ordered factorizations over least prime signatures. The unordered version is described by sequence A129306.at n=43A131420
- Triangle read by rows: T(n,k) is the number of deco polyominoes of height n with k cells in the second row (0<=k<=n-1; a deco polyomino is a directed column-convex polyomino in which the height, measured along the diagonal, is attained only in the last column).at n=32A134436
- a(n) = n*(5*n-3).at n=40A135706
- Row sums of A057282.at n=3A151615
- Number of right triangles with nonnegative integer coordinates less than or equal to n and one corner at the origin.at n=38A155154
- Numerators of EH(n), the expected value of the height of a probabilistic skip list with n elements and p=1/2.at n=6A158466
- a(n) = Hermite(n,10).at n=3A158534
- The 3rd Hermite Polynomial evaluated at n: H_3(n) = 8*n^3 - 12*n.at n=10A163322
- The number of functions in a finite set for which the sequence of composition powers ends in a length 3 cycle.at n=6A163952
- (Average of twin balanced prime pairs)/10.at n=26A173893