5211
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 9
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 7760
- Proper Divisor Sum (Aliquot Sum)
- 2549
- 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
- 3456
- Möbius Function
- 0
- Radical
- 579
- Omega Function (Ω)
- 4
- 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
- yes
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 134
- 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
- no
- Odd
- yes
Appears in sequences
- a(n) = ceiling(n*phi^13), where phi is the golden ratio, A001622.at n=10A004968
- Number of directed animals of size n (k=1 column of A038622); number of (s(0), s(1), ..., s(n)) such that s(i) is a nonnegative integer and |s(i) - s(i-1)| <= 1 for i = 1,2,...,n, where s(0) = 2; also sum of row n+1 of array T in A026323.at n=9A005774
- Coordination sequence T2 for Zeolite Code SGT.at n=45A008230
- Arrange digits of squares in descending order.at n=39A028908
- Numbers k that divide the (right) concatenation of all numbers <= k written in base 13 (most significant digit on left).at n=31A029458
- Lucky numbers with size of gaps equal to 20 (upper terms).at n=10A031903
- Take list of squares, move left digit of each term to end of previous term.at n=40A032760
- Decimal part of a(n)^(1/2) starts with a 'nine digits' anagram.at n=3A034277
- Positive numbers having the same set of digits in base 5 and base 8.at n=37A037431
- Positive numbers having the same set of digits in base 7 and base 8.at n=44A037438
- Triangular array that counts rooted polyominoes.at n=46A038622
- Starting positions of strings of 2 3's in the decimal expansion of Pi.at n=39A050222
- Square array read by antidiagonals: number of ways a pawn-like piece (with the initial 2-step move forbidden and starting from any square on the back rank) can end at various squares on an infinite chessboard.at n=63A062105
- Let P(k) = floor(k/2). Start with n, apply P repeatedly until reach 1. a(n) = concatenation of numbers obtained.at n=8A083177
- Least k such that decimal representation of k*n contains only digits 0 and 9.at n=18A096688
- Triangle, read by rows, of pairwise sums of trinomial coefficients (A027907).at n=50A104029
- Number of partitions that are "2-close" to being self-conjugate.at n=41A108961
- Partial sum of Catalan numbers A000108 multiplied by powers of 10.at n=3A112704
- Riordan array (1/sqrt(1-2*x-3*x^2), M(x)-1) where M(x) is the g.f. of the Motzkin numbers A001006.at n=46A114422
- Triangle whose k-th column has e.g.f. exp(x)*sum{j=0..k, Bessel_I(k+j,2x)}.at n=46A116401