1659
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
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 2560
- Proper Divisor Sum (Aliquot Sum)
- 901
- 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
- 936
- Möbius Function
- -1
- Radical
- 1659
- 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
- yes
- 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
- Denominators of cosecant numbers: -2*(2^(2*n-1)-1)*Bernoulli(2*n).at n=39A001897
- Number of distinct values taken by 3^3^...^3 (with n 3's and parentheses inserted in all possible ways).at n=10A003018
- Numbers n such that n! has a square number of digits.at n=32A006488
- Denominators of expansion of sinh x / sin x.at n=39A006656
- Coordination sequence T5 for Zeolite Code MEL.at n=26A008154
- Pisot sequence E(9,15), a(n) = floor( a(n-1)^2/a(n-2) + 1/2 ).at n=10A014003
- Number of elements in the set {(x,y): 1 <= x,y <= n, gcd(x,y)=1}.at n=51A018805
- a(n) = n*(17*n - 1)/2.at n=14A022274
- Coordination sequence T3 for Zeolite Code CGS.at n=30A027367
- Numbers n such that n divides the (right) concatenation of all numbers <= n written in base 10 (most significant digit on right).at n=14A029503
- 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 26.at n=15A031524
- Lucky numbers with size of gaps equal to 14 (upper terms).at n=7A031897
- Lucky numbers indexed by the lucky numbers (Lucky numbers with lucky number subscripts).at n=45A032639
- Coordination sequence T9 for Zeolite Code STT.at n=27A038424
- Coordination sequence T2 for Zeolite Code SFF.at n=27A038438
- Denominators of continued fraction convergents to sqrt(682).at n=6A042311
- Numerators of continued fraction convergents to sqrt(716).at n=4A042378
- a(n)=(s(n)+7)/9, where s(n)=n-th base 9 palindrome that starts with 2.at n=42A043073
- Numbers k such that 3 and 4 occur juxtaposed in the base-9 representation of k but not of k-1.at n=41A043201
- Numbers k such that 5 and 9 occur juxtaposed in the base-10 representation of k but not of k-1.at n=32A043254