1791
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 2600
- Proper Divisor Sum (Aliquot Sum)
- 809
- 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
- 1188
- Möbius Function
- 0
- Radical
- 597
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 99
- 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
- a(n) = floor(1000*log(n)).at n=5A004240
- a(n) = floor(n*phi^11), where phi is the golden ratio, A001622.at n=9A004926
- a(n) = round(n*phi^11), where phi is the golden ratio, A001622.at n=9A004946
- Number of aperiodic binary necklaces of length n with no subsequence 00, excluding the necklace "0".at n=21A006206
- Coordination sequence T1 for Zeolite Code AFT.at n=32A008026
- Year of birth of n-th President of U.S.A.at n=14A008745
- a(n) = 2*a(n-2) + 1.at n=17A010737
- Positive integers n such that 2^n (mod n) == 2^9 (mod n).at n=75A015931
- Five iterations of Reverse and Add are needed to reach a palindrome.at n=40A015982
- Define the generalized Pisot sequence T(a(0),a(1)) by: a(n+2) is the greatest integer such that a(n+2)/a(n+1) < a(n+1)/a(n). This is T(3,9).at n=6A018919
- Numbers k such that the continued fraction for sqrt(k) has period 20.at n=43A020359
- Largest value of k for which Golay-Rudin-Shapiro sequence A020986(k) = n.at n=47A020991
- a(n) = n*(11*n+1)/2.at n=18A022269
- Numbers k such that Fibonacci(k) == 34 (mod k).at n=19A023180
- Convolution of odd numbers and A014306.at n=45A023661
- Discriminants of quartic fields with 2 complex conjugates (negated).at n=38A023681
- Coordination sequence T1 for Zeolite Code MWW.at n=28A024986
- [ 3rd elementary symmetric function of {sqrt(k+1)} ], k = 1,2,...,n.at n=7A025220
- a(n) = Sum_{k=0..floor(n/2)} A026615(n, k).at n=11A026623
- Duplicate of A022269.at n=17A026817