9980
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 26
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 21000
- Proper Divisor Sum (Aliquot Sum)
- 11020
- 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
- 3984
- Möbius Function
- 0
- Radical
- 4990
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 73
- 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 connected graphs on n labeled nodes, each node being colored with one of 5 colors, such that no edge joins nodes of the same color.at n=4A002030
- Sum{T(n,k)}, k = 0,1,...,n, where T is the array defined in A026082.at n=9A026096
- Numbers that reach the fixed point 89 under iteration of f(x) = reverse(x) - maxdigit(x).at n=13A097155
- Positive integers n such that n^14 + 1 is semiprime (A001358).at n=40A104335
- Numbers n such that every digit of both n and n^2 contains a loop (only digits 0,4,6,8,9 in n and n^2).at n=17A107626
- Composite numbers between largest n-digit prime and the smallest (n+1) digit prime.at n=23A109936
- a(n) = prime(n)^2 - prime(n^2). Commutator of (primes, squares) at n.at n=33A123914
- Numbers k such that k and k^2 use only the digits 0, 4, 6, 8 and 9.at n=18A136956
- a(n) = 25*n^2 - n.at n=19A157514
- a(n) = 1000*n - 20.at n=9A157515
- a(n) = 100*n^2 - 2*n.at n=10A158129
- a(n) = 400*n^2 - 20.at n=4A158597
- Sum over all partitions of n of the LCM of the parts.at n=18A181844
- a(n) = n^4 - 2n.at n=10A246767
- Number of unlabeled rooted trees with n nodes where the outdegrees (branching factors) of adjacent nodes differ by exactly one.at n=57A257654
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 934", based on the 5-celled von Neumann neighborhood.at n=31A273794
- Ulam numbers k such that 4*k and 16*k are also Ulam numbers.at n=13A287634
- Array read by antidiagonals: T(n,k) is the number of connected graphs on n labeled nodes, each node being colored with one of k colors, where no edge connects two nodes of the same color.at n=49A322279
- Number of integer partitions of n containing all of their distinct multiplicities.at n=41A325705
- Two-column array read by rows, where the n-th row is the least pair of integers (p, q) such that f(p) = f(n) + q*f(n+1) where f(n) = A002496(n) is the n-th prime of the form k^2+1.at n=7A352582