13770
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 40
- Divisor Sum
- 39204
- Proper Divisor Sum (Aliquot Sum)
- 25434
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 3456
- Möbius Function
- 0
- Radical
- 510
- Omega Function (Ω)
- 7
- Little Omega Function (ω)
- 4
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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 58
- 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
- Let F(x) = 1 + x + 4x^2 + 9x^3 + ... = g.f. for A002835 (solid partitions restricted to two planes) and expand (1-x)*(1-x^2)*(1-x^3)*...*F(x) in powers of x.at n=16A005980
- A convolution triangle of numbers obtained from A034171.at n=41A035529
- Maximal number of regions into which 5-space can be divided by n hyperspheres.at n=17A059174
- a(n) = 3*n*(4*n-1).at n=34A062783
- Smaller terms in the pairs of numbers (a < b) in the sequence {a,b}-> {Max[{a,b}]-Min[{a,b}],k*Min[{a,b}]} with k=3 and the first pair {a=1,b=2}. See A075256.at n=46A075257
- Square spiral of sums of selected preceding terms, starting at 1 (a spiral Fibonacci-like sequence).at n=20A094768
- Nonprime-power sigma-perfect numbers: numbers n such that NPPSigma(n)=2*n, where, if n=Product p_i^r_i then NPPSigma(n)=Product{Sum p_i^s_i, s_i is not a prime number, 0<=s_i<=r_i}.at n=2A099723
- Numbers k for which nontrivial positive magic squares of exactly 9 different orders with magic sum k exist. For a definition of nontrivial positive magic squares, see A125005.at n=28A125016
- a(n) = prime(3^(n + 1)) - prime(3^n).at n=6A135371
- Shifts 3 places left under Dirichlet convolution.at n=40A144367
- Triangle T, read by rows, where the matrix square T^2 results in shifting T right one column to drop the secondary diagonal.at n=48A152391
- a(n) = n^3/6 + 3*n^2/4 + 7*n/3 + 7/8 + (-1)^n/8.at n=42A173154
- Numbers k such that k^2 +-11 are primes.at n=40A176683
- Numbers of the form p^4*q*r*s where p, q, r, and s are distinct primes.at n=37A179693
- Numbers n such that 3 and 5 do not divide swing(n) = A056040(n).at n=39A196748
- Solution of the complementary equation a(n) = 2*a(n-1) - a(n-2) + b(n-1) + 1, where a(0) = 1, a(1) = 2, b(0) = 3, and (a(n)) and (b(n)) are increasing complementary sequences.at n=39A294869
- Partial sums of A033616.at n=30A299902
- Number of nX5 0..1 arrays with every element unequal to 0, 1, 3, 5, 7 or 8 king-move adjacent elements, with upper left element zero.at n=7A316612
- Semi-unitary perfect numbers: numbers k such that susigma(k) = 2k, where susigma(k) is the sum of the semi-unitary divisors of k (A322485).at n=7A322486
- Number of n-step closed paths on the Cairo pentagonal lattice graph starting from a degree-3 node.at n=11A357811