7443
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
- 10764
- Proper Divisor Sum (Aliquot Sum)
- 3321
- 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
- 4956
- Möbius Function
- 0
- Radical
- 2481
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 70
- 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 Fib(k) == -34 (mod k).at n=44A023169
- 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 85.at n=17A031583
- Take list of cubes, move left digit of each term to end of previous term.at n=15A032761
- n plus a googol is prime.at n=21A049014
- a(n) equals floor(Vc(n) - Vs(n)), where Vc(n) is the volume of the cube with side length n and Vs(n) is the volume of the sphere of diameter n.at n=24A057671
- Numbers k such that both k and the k-th prime have nonincreasing digits.at n=39A116067
- Expansion of x * (x+1) * (x^3-x^2-1) / ((x^2+1) * (x^3+x^2-1)).at n=34A122519
- Expansion of g.f.: x^4/((1+2*x) * (1-2*x+x^2+2*x^3)).at n=17A123957
- a(1) = 8127; thereafter a(n) = (a(n-1) with digits sorted into descending order) - (a(n-1) with digits sorted into ascending order) (see the Kaprekar map, A151949).at n=1A151946
- a(n) = 121*n^2 - 38*n + 3.at n=7A157443
- Numbers of the form x^2 + y^2 + z^2 = phi(x*y*z) + sigma(x*y*z).at n=19A173792
- G.f. satisfies: x = Sum_{n>=1} 1/A(x)^(4*n) * Product_{k=1..n} (1 - 1/A(x)^k).at n=6A181998
- Inverse permutation to A190126.at n=26A190127
- Numbers n such that d(n-1) = d(n+1) = 6, where d(k) is the number of divisors of k (A000005).at n=29A190267
- Number of equivalence classes of lattices of subsets of the power set 2^[n].at n=5A235604
- The hyper-Wiener index of the hexagonal triangle T_n, defined in the He et al. reference.at n=4A248094
- Indices of primes in the 7th-order Fibonacci number sequence, A060455.at n=37A253318
- Partial sums of A009927.at n=11A265038
- Triangle read by rows in which each new term is the sum of its two largest neighbors in the structure.at n=32A278645
- Compound filter (summands of A004001 & summands of A005185): a(n) = P(A286541(n), A286559(n)), where P(n,k) is sequence A000027 used as a pairing function, with a(1) = a(2) = 0.at n=19A286560