7440
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 40
- Divisor Sum
- 23808
- Proper Divisor Sum (Aliquot Sum)
- 16368
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 1920
- Möbius Function
- 0
- Radical
- 930
- 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
- 39
- 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
- Sorting numbers (see Motzkin article for details).at n=6A002875
- Number of Hamiltonian paths in K_3 X P_n.at n=5A003689
- Number of n-bead bracelets (turnover necklaces) with 8 red beads and n-8 black beads.at n=14A005514
- G.f.: 2*(1-x^3)/((1-x)^5*(1+x)^2).at n=29A005996
- a(n) = floor(n*(n-1)*(n-2)/4).at n=32A011886
- Areas of right triangles with coprime integer sides.at n=36A024365
- Ordered areas of primitive Pythagorean triangles.at n=38A024406
- Numbers k that divide the (left) concatenation of all numbers <= k written in base 19 (most significant digit on left).at n=35A029488
- Numbers k such that A102489(k) is divisible by k.at n=30A032563
- Total number of possible knight moves on an (n+2) X (n+2) chessboard, if the knight is placed anywhere.at n=30A035008
- Numbers whose base-3 representation has exactly 9 runs.at n=14A043589
- Numbers n such that number of runs in the base 3 representation of n is congruent to 1 mod 8.at n=30A043799
- Numbers n such that number of runs in the base 3 representation of n is congruent to 0 mod 9.at n=14A043806
- Numbers k such that number of runs in the base 3 representation of k is congruent to 9 mod 10.at n=14A043824
- Denominator of b(n)-b(n+1), where b(n) = n/((n+1)(n+2)) = A026741/A045896.at n=28A051713
- Sum of transposition distances (divided by 2) present in the permutation produced by inverses of 1..(p-1) computed in Zp, where p is n-th prime.at n=46A051864
- E.g.f.: log(-(-1+x)^2/(-1+2*x)).at n=6A052867
- Least k for which the integers floor(2k/(m*(m+1))) for m=1,2,...,n are distinct.at n=34A054064
- Smallest area of a Pythagorean triangle with n as length of one of the three sides.at n=28A054435
- Smallest area of a Pythagorean triangle with n as length of a leg.at n=28A054436