7904
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
- 1
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 17640
- Proper Divisor Sum (Aliquot Sum)
- 9736
- 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
- 3456
- Möbius Function
- 0
- Radical
- 494
- Omega Function (Ω)
- 7
- 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
- 52
- 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
- Triangle of coefficients of expansions of powers of x in terms of Legendre polynomials P_n(x) over common denominator.at n=33A008317
- Number of segments created by diagonals of n-gon.at n=16A014629
- Expansion of 1/(1-x^5-x^6-x^7-x^8-x^9-x^10-x^11-x^12-x^13-x^14-x^15).at n=40A017846
- [ exp(9/20)*n! ].at n=6A030856
- 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=32A031541
- Numbers ending with '4' that are the difference of two positive cubes.at n=21A038859
- Numbers k such that prime(k+1)^2 == prime(k)^2 (mod k).at n=28A067783
- Lexicographically earliest increasing sequence of relatively prime numbers with nondecreasing number of divisors. a(0) = 1, tau(a(n+1)) >= tau(a(n)) and GCD(a(n),a(n+1)) = 1.at n=41A076963
- Number of palindromes that use nonzero digits and have a digit sum of n.at n=26A082267
- Number of palindromes that use nonzero digits and have a digit sum of n.at n=25A082267
- Let M = the 2 X 2 matrix [0 1 / -1 2+sqrt(8)]. Perform the operation M^n * [1 1] = [x y]; then a(n) = floor(x), a(n+1) = floor(y).at n=6A093568
- Number of subsets of {1,2,...,n} such that every number in the set is no larger than the sum of the other numbers in the set.at n=12A095941
- Expansion of (-1+x^3+x^6+x^9)/((1-x)*(2*x-1)*(x^2+1)*(x^2+x+1)*(x^4-x^2+1)).at n=13A111663
- a(n) = numerator of Product_{k=1..n} k^mu(n+1-k), where mu(k) = A008683(k).at n=32A130088
- 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, 1), (1, -1, -1), (1, -1, 1), (1, 1, 0)}.at n=8A149209
- 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), (0, 0, -1), (0, 1, 0), (1, 0, 0)}.at n=9A149819
- 4 times octagonal numbers: a(n) = 4*n*(3*n-2).at n=26A153794
- a(n) = n*(2*n^2 + 5*n + 15)/2.at n=19A163673
- G.f. satisfies: A(x) = 1 + x*A(x)^2 / (A(I*x) * A(-I*x)).at n=9A212527
- a(n) = floor(n/2)^3 - floor(n/3)^3.at n=44A213031