1909
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
- 4
- Divisor Sum
- 2016
- Proper Divisor Sum (Aliquot Sum)
- 107
- 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
- 1804
- Möbius Function
- 1
- Radical
- 1909
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 37
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- a(n) = n*a(n-1) + (n-5)*a(n-2).at n=5A001910
- Numbers that are the sum of 12 positive 6th powers.at n=32A003368
- Losing initial positions in game: two players alternate in removing >= 1 stones; last player wins; first player may not remove all stones; each move <= 3 times previous move.at n=22A003411
- Maximal planar degree sequences with n nodes.at n=11A007020
- Optimal cost of search tree for searching an ordered array of n elements with cost k of probing element k.at n=29A007077
- Hyperperfect numbers: k = m*(sigma(k) - k - 1) + 1 for some m > 1.at n=5A007592
- Coordination sequence T5 for Zeolite Code BOG.at n=31A008053
- Coordination sequence T2 for Zeolite Code MTN.at n=26A008187
- Coordination sequence T1 for Zeolite Code -PAR.at n=31A009855
- a(n) = Sum_{k=0..n} ceiling(k^3/n).at n=18A014813
- Position of n^3 + (n+1)^3 in A003325.at n=51A024669
- Partial sums of the sequence of prime powers (A000961).at n=40A024918
- 9th-order Vatalan numbers (generalization of Catalan numbers).at n=3A025762
- Number of distinct products ijk with 1 <= i,j,k <= n.at n=29A027425
- 18-hyperperfect numbers: n = 18*(sigma(n)-n-1) + 1.at n=1A028501
- Numbers whose set of base-12 digits is {1,3}.at n=16A032919
- a(n) = n * prime(n).at n=22A033286
- Hyperperfect numbers: x such that x = 1 + k*(sigma(x)-x-1) for some k > 0.at n=8A034897
- First differences give (essentially) A028242.at n=24A035107
- Number of partitions of n with equal nonzero number of parts congruent to each of 0 and 2 (mod 3).at n=35A035538