9820
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
- 1
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 20664
- Proper Divisor Sum (Aliquot Sum)
- 10844
- 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
- 3920
- Möbius Function
- 0
- Radical
- 4910
- Omega Function (Ω)
- 4
- 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
- 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
- Number of partitions of n with equal number of parts congruent to each of 1 and 2 (mod 4).at n=47A035543
- Indices of primes in the sequence defined by A(0) = 23, A(n) = 10*A(n-1) - 27 for n > 0.at n=17A101951
- a(n) = 250*n - 180.at n=40A154360
- Irregular array read by rows: T(n,k) = number of r_{n,k}-cores associated with A233332(n,k), for n>=2, 1<=k<=floor(n/2), explained below.at n=34A233330
- Number of (n+2)X(2+2) 0..1 arrays with no 3x3 subblock diagonal sum 0 or 1 and no antidiagonal sum 0 or 1 and no row sum 1 and no column sum 1.at n=5A256023
- Number of (n+2)X(6+2) 0..1 arrays with no 3x3 subblock diagonal sum 0 or 1 and no antidiagonal sum 0 or 1 and no row sum 1 and no column sum 1.at n=1A256027
- T(n,k)=Number of (n+2)X(k+2) 0..1 arrays with no 3x3 subblock diagonal sum 0 or 1 and no antidiagonal sum 0 or 1 and no row sum 1 and no column sum 1.at n=22A256029
- T(n,k)=Number of (n+2)X(k+2) 0..1 arrays with no 3x3 subblock diagonal sum 0 or 1 and no antidiagonal sum 0 or 1 and no row sum 1 and no column sum 1.at n=26A256029
- Numbers whose abundance is a power of 2.at n=39A259174
- Number of (n+1)X(2+1) 0..4 arrays with each row and column divisible by 13, read as a base-5 number with top and left being the most significant digits.at n=4A263435
- Number of (n+1)X(5+1) 0..4 arrays with each row and column divisible by 13, read as a base-5 number with top and left being the most significant digits.at n=1A263438
- T(n,k)=Number of (n+1)X(k+1) 0..4 arrays with each row and column divisible by 13, read as a base-5 number with top and left being the most significant digits.at n=16A263439
- T(n,k)=Number of (n+1)X(k+1) 0..4 arrays with each row and column divisible by 13, read as a base-5 number with top and left being the most significant digits.at n=19A263439
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 369", based on the 5-celled von Neumann neighborhood.at n=23A268503
- Number of aperiodic necklaces (Lyndon words) with k<=6 black beads and n-k white beads.at n=25A277631
- Triangle read by rows in which each new term is the sum of its two largest neighbors in the structure.at n=38A278645
- Fixed points of the transform A284803.at n=44A284804
- Rectangular array read by antidiagonals: a(m,n) = 2 * Integral_{t>=0} T_n((t+m)/2)*exp(-t)*dt, m>=0, n>=0, where T_n(x) is n-th Chebyshev polynomial of first kind.at n=60A300480
- Number of unlabeled rooted semi-identity trees with n nodes.at n=13A306200
- Even integers x such that x + sqrt(y) = sqrt(x || y), where || denotes decimal concatenation and y is a perfect square.at n=40A390123