9912
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 32
- Divisor Sum
- 28800
- Proper Divisor Sum (Aliquot Sum)
- 18888
- 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
- 2784
- Möbius Function
- 0
- Radical
- 2478
- Omega Function (Ω)
- 6
- 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
- yes
- Harshad Number
- yes
- 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 into one kind of 1's, two kinds of 2's, and three kinds of 3's.at n=35A002597
- Number of achiral rooted trees.at n=24A003241
- Number of graceful permutations of length n.at n=14A006967
- a(n) = a(1)*a(n-1) + a(2)*a(n-2) + ...+ a(n-1)*a(1) for n >= 3, with initial terms 2,3.at n=6A025231
- Number of partitions of n into parts not of the form 19k, 19k+7 or 19k-7. Also number of partitions with at most 6 parts of size 1 and differences between parts at distance 8 are greater than 1.at n=34A035976
- Row 6 of square array defined in A047662.at n=6A047663
- Row 7 of square array defined in A047662.at n=5A047664
- Number of planar rooted trees with n nodes and tricolored end nodes.at n=6A047891
- A triangle of numbers related to triangle A030527.at n=33A049374
- a(n) is the smallest number which when written in binary contains as substrings the binary expansions of 1..n.at n=12A056744
- a(n) is the smallest number which when written in binary contains as substrings the binary expansions of 1..n.at n=13A056744
- Dimension of the space of weight n cuspidal newforms for Gamma_1( 85 ).at n=38A063358
- Treated as strings, n begins with Floor(sqrt(n)).at n=35A069086
- a(n) = number of partitions of n wherein the sum of the 1's is no more than the sum of the other parts.at n=32A083690
- Smallest number containing in its binary representation substrings forming an arithmetic progression exactly of size n.at n=14A091461
- Numbers that can be expressed as the difference of the squares of primes in exactly four distinct ways.at n=27A092000
- Number of ways to label the vertices of the octahedron (or faces of the cube) with nonnegative integers summing to n, where labelings that differ only by rotation or reflection are considered the same.at n=31A097513
- Round(1000*x), where x is the solution to x = 3^(n-x).at n=12A103537
- Triangular matchstick numbers in the class of prime numbers: sum of n-th and next n primes.at n=36A105720
- Number of primitive Pythagorean-like triples a^2+b^2=c^2+k for k=2 with 0<c<=10^n.at n=4A121084