9905
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 23
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 13632
- Proper Divisor Sum (Aliquot Sum)
- 3727
- 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
- 6768
- Möbius Function
- -1
- Radical
- 9905
- 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
- 42
- 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
- no
- Odd
- yes
Appears in sequences
- Treated as strings, n begins with Floor(sqrt(n)).at n=28A069086
- Sums of p-th to the q-th prime where p and q are consecutive primes.at n=29A114381
- Numbers k such that tau(k) = tau(k+1) mod 691, where tau is Ramanujan's tau function A000594.at n=12A121733
- a(n) = n*(8*n+3).at n=35A139276
- Triangle T(n,k) = number of forests of labeled rooted trees of height at most 1, with n labels, k of which are used for root nodes and any root may contain >= 1 labels, n >= 0, 0<=k<=n.at n=32A143396
- Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 11000-01100-00110-00011 pattern in any orientation.at n=11A147451
- Number of nXnXn triangular nonnegative integer arrays with all sums of an element and its neighbors <= 10.at n=3A166182
- Number of 3 X 3 X 3 triangular nonnegative integer arrays with all sums of an element and its neighbors <= n.at n=10A166189
- Partial sums of A000132.at n=20A175360
- Integers n such that both 2*n^2 + 3*(n+2)^2 and 3*n^2 + 2*(n+2)^2 are prime.at n=35A216849
- Number of 3Xn arrays of the minimum value of corresponding elements and their horizontal or diagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..2 3Xn array.at n=8A220155
- Fundamental discriminants d uniquely characterizing all complex biquadratic fields Q(sqrt(-3),sqrt(d)) which have 3-class group of type (3,3) and second 3-class group isomorphic to SmallGroup(729,34).at n=5A250241
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 149", based on the 5-celled von Neumann neighborhood.at n=24A270319
- Number of forests of labeled rooted trees of height at most 1, with n labels, four of which are used for root nodes and any root may contain >= 1 labels.at n=3A273654
- Positions of ones in A264977; positions of twos in A277330.at n=56A277701
- Number of compositions of n whose run-lengths are either weakly increasing or weakly decreasing.at n=16A332835
- k such that L(H(k,1)^2) = 2*L(H(k,1)) where L(x) is the number of terms in the continued fraction of x and H(k,r) = Sum_{u=1..k} 1/u^r.at n=40A336089
- Trajectory of initial value 89 under iterations of the map A352544: half if even, add largest anagram if odd.at n=8A352542
- Numbers k such that A308485(k) is a multiple of k.at n=10A352698
- Expansion of (1/x) * Series_Reversion( x*(1+x)^3*(1-x)^4 ).at n=7A365878