5176
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 9720
- Proper Divisor Sum (Aliquot Sum)
- 4544
- 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
- 2584
- Möbius Function
- 0
- Radical
- 1294
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 41
- 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(2n) = a(2n-1) + 2a(2n-2), a(2n+1) = a(2n) + a(2n-1), with a(1) = 2 and a(2) = 3.at n=13A001882
- Centered pentagonal numbers: (5n^2+5n+2)/2; crystal ball sequence for 3.3.3.4.4. planar net.at n=45A005891
- Numbers k such that Fib(k) == -21 (mod k).at n=41A023168
- n written in fractional base 9/5.at n=51A024653
- a(n) = Sum_{k=1..n} (n-k) * floor(n/k).at n=40A024920
- a(n) = (1/C(n,0) + 1/C(n,1) + ... + 1/C(n,n))*L, where L = LCM{C(n,0), C(n,1),..., C(n,n)}.at n=11A025533
- Numbers k such that 231*2^k+1 is prime.at n=42A032492
- a(n)=(s(n)+2)/9, where s(n)=n-th base 9 palindrome that starts with 7.at n=28A043078
- Number of conjugacy classes of elements of order n in 2.E_7(C).at n=20A045515
- Number of nonnegative integer 2 X 2 matrices with no zero rows or columns and with sum of elements equal to n, up to row and column permutation.at n=46A054974
- Maximal value of Sum_{i=1..n} (p(i) - p(i+1))^2, where p(n+1) = p(1), as p ranges over all permutations of {1, 2, ..., n}.at n=24A064842
- Number of labeled 2-chromatic (i.e., chromatic number = 2) graphs on n nodes.at n=5A084270
- a(n) = n*(n^2+3*n-1)/3.at n=24A084990
- 45-gonal numbers: n*(43*n-41)/2.at n=15A098924
- The PDO(n) function (Partitions with Designated summands in which all parts are Odd): the sum of products of multiplicities of parts in all partitions of n into odd parts.at n=31A102186
- This sequence and A139143 are complements. a(1) = 1, A139143(1) = 2, a(n+1) = a(n) + Sum_{k = 1..n} A139143(k).at n=28A139142
- Number of 2's in row n of A143589 (a Kolakoski fan).at n=24A143592
- Triangle read by rows: expansion of p(x,n)=If[n == 0, 1, (x + 1)^n + 2^(n+1)*Sum[Binomial[n-m, m]*x^m*(1 + x^(n - 2*m)), {m, 1, n - 1}]].at n=41A146774
- Triangle read by rows: expansion of p(x,n)=If[n == 0, 1, (x + 1)^n + 2^(n+1)*Sum[Binomial[n-m, m]*x^m*(1 + x^(n - 2*m)), {m, 1, n - 1}]].at n=39A146774
- a(n) = 2*n^2 + 16*n + 6.at n=46A154590