5571
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 8060
- Proper Divisor Sum (Aliquot Sum)
- 2489
- 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
- 3708
- Möbius Function
- 0
- Radical
- 1857
- Omega Function (Ω)
- 3
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 67
- 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
- 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 73.at n=23A031571
- Number of dissections of a convex polygon by nonintersecting diagonals into polygons with even number of sides and having a total number of n edges (sides and diagonals).at n=18A067955
- Interprimes which are of the form s*prime, s=9.at n=14A075284
- Perfect totient numbers.at n=19A082897
- Perfect totient numbers, omitting powers of 3.at n=12A091847
- Antidiagonal sums of symmetric square array A101515 and also equals the binomial transform of a sequence formed from terms of A101514 repeated twice.at n=10A101516
- Sum of the primes in ordered 3 X 3 prime squares.at n=12A105089
- Numbers n such that pi(n)=pi(d_1!)+pi(d_2!)+...+pi(d_k!) where d_1 d_2 ...d_k is the decimal expansion of n.at n=8A105327
- Positive integers n such that S(n) divides n, where S(n) is the sum of the iterates of the Euler phi-function of n, that is, S(n) = phi(n)+phi(phi(n))+....+ 1.at n=37A113808
- Number of n X n symmetric 0..5 arrays with no element equal to the sum mod 6 of any two of its horizontal and vertical neighbors.at n=2A193223
- Sum of the first n binary palindromes; a(n) = Sum_{k=1..n} A006995(k).at n=39A206920
- Number of ordered triples (w,x,y) with all terms in {1,...,n} and 2w^2>x^2+y^2.at n=22A211810
- Number of (n+3) X 7 0..1 matrices with each 4 X 4 subblock idempotent.at n=11A224564
- Number of partitions of n for which 2*(number of distinct parts) > (number of parts).at n=35A237365
- Numbers k such that the smallest k-digit odd number concatenated with the largest k-digit odd number is prime.at n=4A247182
- Numbers k for which the digital product A007954(k) contains the same distinct digits as the number k.at n=38A249516
- Number T(n,k) of permutations p of [n] with no fixed points where the maximal displacement of an element equals k; triangle T(n,k), n>=0, 0<=k<=n, read by rows.at n=42A259784
- Integers k such that k^2 + 1 = 2*p where p and p+2 are twin primes.at n=37A261542
- Number of n X 2 binary arrays with rows and columns lexicographically nondecreasing and column sums nonincreasing.at n=40A266464
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 217", based on the 5-celled von Neumann neighborhood.at n=19A270911