5906
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
- 4
- Divisor Sum
- 8862
- Proper Divisor Sum (Aliquot Sum)
- 2956
- 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
- 2952
- Möbius Function
- 1
- Radical
- 5906
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 124
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- Number of free planar polyenoids with 2n nodes and symmetry point group C_{2h}.at n=9A000935
- For any circular arrangement of 0..n-1, let S = sum of squares of every sum of two contiguous numbers; then a(n) = # of distinct values of S.at n=32A007773
- Expansion of (1+x^2)(1+x^4)/((1-x)^2*(1-x^2)*(1-x^3)).at n=37A007979
- Numbers k such that the continued fraction for sqrt(k) has period 15.at n=29A020354
- a(n) = floor( (Pi/e)^n ).at n=60A032739
- Numbers k such that x^4 + y^4 = k * z^4 is solvable in nonzero integers x,y,z.at n=34A060387
- a(n) is twice the least possible area enclosed by a convex lattice n-gon.at n=53A070911
- Triangle read by rows: T(n,k) = number of peakless Motzkin paths of length n containing k U H^j Us for some j>0, where U=(1,1) and H=(1,0) (can be easily expressed using RNA secondary structure terminology).at n=29A097777
- Number of peakless Motzkin paths with no U H...HU's where U=(1,1) and H=(1,0) (can be easily expressed using RNA secondary structure terminology).at n=14A098051
- Period of the first difference of Ulam 1-additive sequence U(2,2n+1).at n=4A100729
- Smallest number that is a sum of two n-th powers of positive rationals but not of two n-th powers of positive integers.at n=1A111152
- Semiprimes (A001358) that are sums of distinct factorials.at n=36A115646
- Numbers k such that 2^k, 3^k, 5^k, 7^k, 11^k, 13^k, 17^k and 19^k have even digit sum.at n=23A119897
- Triangle read by rows: T(n,k) is the number of deco polyominoes of height n having k cells in the first two columns (n>=1, k>=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=49A121583
- Positions of harmonic numbers in the EKG sequence.at n=9A140804
- Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of n steps taken from {(-1, 1), (0, -1), (1, -1), (1, 0), (1, 1)}.at n=9A151461
- a(n) = 2*(n^3 + n^2 + n - 1).at n=14A155120
- G.f. 1/(1-sum(n=1,N,x^(n*(3*n-1)/2))).at n=32A181324
- a(n) is the limiting term of the n-th column of the triangle in A188919.at n=18A188920
- Inverse permutation to A190126.at n=2A190127