15904
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 36288
- Proper Divisor Sum (Aliquot Sum)
- 20384
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6720
- Möbius Function
- 0
- Radical
- 994
- 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
- 27
- 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) = (n+1)*(n^2+n+2)/2; g.f.: (1 + 2*x^2) / (1 - x)^4.at n=31A006000
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = (F(2), F(3), ...), t = (odd natural numbers).at n=22A024592
- Numbers k such that k*(k + 9) is a palindrome.at n=13A028570
- Expansion of (theta_3(z)*theta_3(23z)+theta_2(z)*theta_2(23z))^4.at n=33A028660
- Least term in period of continued fraction for sqrt(n) is 9.at n=15A031433
- Moments of generalized Motzkin paths.at n=13A053441
- a(n) = Sum_{k=0..n} 3^(n-k)*A123125(n, k).at n=6A122704
- 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, 0), (0, 0, 1), (0, 1, -1), (1, 0, 0), (1, 1, -1)}.at n=8A150101
- a(n) = 81*n^2 + 2*n.at n=13A177099
- Number of (w,x,y,z) with all terms in {1,...,n} and w<|x-y|+|y-z|.at n=13A212568
- Principal diagonal of the convolution array A213774.at n=11A213775
- First number beginning the smallest chain of n consecutive even divisors distanced no more than 2 one from each other, with no odd divisors between, of some factorial s!.at n=8A218707
- Number of nonnegative integer arrays of length n summing to n without equal adjacent values modulo 7.at n=11A221320
- Number of n X 2 0,1 arrays indicating 2 X 2 subblocks of some larger (n+1) X 3 binary array having two adjacent 1's and two adjacent 0's, with rows and columns of the latter in lexicographically nondecreasing order.at n=10A227329
- Dimensions of algebraic generators of Hopf algebra PML_2.at n=5A230884
- Triangle read by rows: T(n,k) = number of crossing connected diagrams in a disk having n crossings and k chords.at n=25A232227
- Triangle read by rows: Catalan triangle of the k-Fibonacci sequence.at n=62A236918
- Convolution triangle of A000958(n+1).at n=58A237596
- Number of partitions of n whose median is not a part.at n=44A238479
- Number of (n+2)X(6+2) 0..1 arrays with every 3X3 subblock sum of the two sums of the diagonal and antidiagonal minus the two minimums of the central column and central row nondecreasing horizontally, vertically and ne-to-sw antidiagonally.at n=34A254905