1611
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 9
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 2340
- Proper Divisor Sum (Aliquot Sum)
- 729
- 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
- 1068
- Möbius Function
- 0
- Radical
- 537
- Omega Function (Ω)
- 3
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 21
- 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
- no
- Odd
- yes
Appears in sequences
- Squares written in base 9.at n=34A002442
- Positive integers n such that 2^n (mod n) == 2^9 (mod n).at n=68A015931
- Number of elements in the set {(x,y): 1 <= x,y <= n, gcd(x,y)=1}.at n=50A018805
- Coordination sequence T1 for Zeolite Code CZP.at n=26A019456
- Describe previous term from the right (method A - initial term is 6).at n=2A022510
- a(n) = least m such that if r and s in {1/1, 1/4, 1/7,..., 1/(3n-2)} satisfy r < s, then r < k/m < s for some integer k.at n=27A024822
- a(n) = least m such that if r and s in {1/1, 1/2, 1/3, ..., 1/n} satisfy r < s, then r < k/m < (k+2)/m < s for some integer k.at n=24A024840
- Numbers that are the sum of 3 nonzero squares in exactly 9 ways.at n=37A025329
- Record values in A030717.at n=53A030721
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 39.at n=11A031537
- Smaller of a pair of consecutive lucky numbers with a gap of 2n.at n=13A031884
- Lucky numbers with size of gaps equal to 12 (upper terms).at n=18A031895
- Numbers k such that 135*2^k+1 is prime.at n=34A032417
- Quotient of 'base-23' division described in A032577.at n=47A032578
- Lucky numbers indexed by the lucky numbers (Lucky numbers with lucky number subscripts).at n=44A032639
- Numbers whose set of base-8 digits is {1,3}.at n=23A032915
- Multiplicity of highest weight (or singular) vectors associated with character chi_143 of Monster module.at n=35A034531
- Concatenations C1 and C2 are both prime (see the comment lines).at n=49A034814
- Concatenations C1 and C2 are both prime (see the comment lines).at n=32A034815
- Limit of the position of the n-th partition into parts 5k+1 or 5k+4 in the list of all integer partitions sorted in reverse lexicographic order, for integers == 0 (mod 5).at n=49A035405