9830
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 17712
- Proper Divisor Sum (Aliquot Sum)
- 7882
- 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
- 3928
- Möbius Function
- -1
- Radical
- 9830
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 3
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
- 135
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- yes
- 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(1) = a(2) = 1, a(2n + 1) = 2*a(2n) and a(2n) = 2*a(2n - 1) + (-1)^n.at n=14A016029
- Base 4 digits are, in order, the first n terms of the periodic sequence with initial period 2,1.at n=6A037489
- Numbers whose base-4 representation contains exactly three 1's and four 2's.at n=20A045104
- Smallest value of x such that M(x) = -n, where M(x) is Mertens's function A002321.at n=38A051401
- Inverse Mertens function: smallest k such that |M(k)| = n, where M(x) is Mertens's function A002321.at n=38A051402
- Numbers k such that 2*10^k + 7*R_k is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=14A056702
- McKay-Thompson series of class 20F for Monster.at n=21A058555
- An inverse to Mertens's function: smallest k >= 2 such that Mertens's function |M(k)| (see A002321) is equal to n.at n=39A060434
- Floor(X/Y) where X = concatenation of the (n+1)-st even number through the (2n)-th even number and Y = concatenation of first n even numbers.at n=10A067091
- Solution to the non-squashing boxes problem (version 2).at n=27A089055
- Expansion of (1-x^2)/((1-2*x)*(1+x^2)).at n=14A100088
- a(n) = 3*a(n-1) + 4*a(n-2), with a(0)=1, a(1)=2.at n=7A122117
- Triangle read by rows: T(n,k) is the number of binary trees with n edges and jump-length equal to k (n >= 0, 0 <= k <= n-2).at n=41A127532
- Expansion of chi(-q)^5 / chi(-q^5) in powers of q where chi() is a Ramanujan theta function.at n=20A138521
- G.f. satisfies: A(x) = x + A(A(A(A(x)))^2).at n=5A141382
- Number of (n+1) X 2 binary arrays with every 2 X 2 subblock diagonal sum less antidiagonal sum equal to some horizontal or vertical neighbor 2 X 2 subblock diagonal sum less antidiagonal sum.at n=11A186120
- Expansion of chi(q)^5 / chi(q^5) in powers of q where chi() is a Ramanujan theta function.at n=20A225701
- Curvature (rounded down) of the circle inscribed in the n-th golden triangle arranged in a spiral form.at n=17A228560
- Related to Pisano periods: numbers n such that there are n+10 distinct Fibonacci numbers mod n.at n=30A229467
- a(n) = n*prime(prime(n)) - prime(n).at n=22A230285