9405
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
- 1
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 18720
- Proper Divisor Sum (Aliquot Sum)
- 9315
- 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
- 4320
- Möbius Function
- 0
- Radical
- 3135
- Omega Function (Ω)
- 5
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 60
- 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
- Degrees of irreducible representations of Harada-Norton group HN.at n=8A003915
- a(n) = n*(13*n + 1)/2.at n=38A022271
- [ 4th elementary symmetric function of {sqrt(k)} ], k = 1,2,...,n.at n=7A025195
- Longest edge a of smallest (measured by the longest edge) primitive Euler bricks (a, b, c, sqrt(a^2 + b^2), sqrt(b^2 + c^2), sqrt(a^2 + c^2) are integers).at n=18A031173
- Denominators of continued fraction convergents to sqrt(87).at n=5A041155
- Denominators of continued fraction convergents to sqrt(348).at n=11A041659
- 9 times octagonal numbers: a(n) = 9*n*(3*n-2).at n=19A064201
- Schroeder pseudoprimes: Composites k that divide the k-th Schroeder number A001003(k-1).at n=19A075764
- a(n) = (4*n+3)*(4*n+7).at n=23A085027
- Odd numbers k such that abs(sigma(k)-2k) <= sqrt(k). Abundance-radius = abs(sigma(k)-2k) does not exceed square root of k and k is odd.at n=8A087415
- a(n) = Jacobsthal(n) * Fibonacci(n+1).at n=9A093122
- Fifth column of the (1,4)-Pascal triangle A095666.at n=17A095667
- a(n) = lcm(A066840(n), A124440(n)).at n=36A124447
- Numbers n for which nontrivial positive magic squares of exactly 10 different orders with magic sum n exist. For a definition of nontrivial positive magic squares, see A125005.at n=13A125017
- Triangle read by rows: (1/3) * (A007318^2 - A007318^(-1)) as infinite lower triangular matrices.at n=57A131048
- Nearest integer to the space diagonal of the smallest (measured by the longest edge) primitive (gcd(a,b,c)=1) Euler bricks (a, b, c, sqrt(a^2 + b^2), sqrt(b^2 + c^2), sqrt(a^2 + c^2) are integers). If the space diagonal is an integer then the Euler brick is called a "perfect cuboid". There are no known perfect cuboids.at n=17A141029
- Third trisection of A061037.at n=31A142600
- Quintisection A061037(5*n+2).at n=19A165248
- a(n) = prime(n)^2-4.at n=24A166010
- Integers n such that 4*prime(n)-+3 are nonconsecutive primes.at n=46A173487