2807
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 3216
- Proper Divisor Sum (Aliquot Sum)
- 409
- 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
- 2400
- Möbius Function
- 1
- Radical
- 2807
- 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
- 128
- 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
- Number of permutations of [n] containing exactly 2 increasing subsequences of length 3.at n=8A001089
- a(n) = floor(1000*log_2(n)).at n=6A004265
- a(n) = round(1000*log_2(n)).at n=6A004266
- Related to representations as sums of Fibonacci numbers.at n=45A006133
- If x and y are terms, so is x*y + 9.at n=22A009350
- Numbers k such that Fib(k) == 13 (mod k).at n=19A023178
- 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 51.at n=24A031549
- Numbers whose set of base-11 digits is {1,2}.at n=25A032931
- Least D in the Pellian x^2 - D*y^2 = 1 for which y has least solution n.at n=52A033318
- Numbers n such that sigma(n) - n = {number of primes <= n}.at n=6A037172
- Numbers k such that us(k) = primepi(k), where us(k) is the sum of the aliquot unitary divisors of k (A034460), and primepi(k) is the number of primes <= k (A000720).at n=8A037176
- Number of partitions satisfying cn(2,5) + cn(3,5) <= 1.at n=35A039857
- Denominators of continued fraction convergents to sqrt(46).at n=10A041079
- Numerators of continued fraction convergents to sqrt(911).at n=3A042760
- Numbers n such that string 5,8 occurs in the base 9 representation of n but not of n-1.at n=38A044304
- Numbers k such that the string 0,7 occurs in the base 10 representation of k but not of k-1.at n=29A044339
- Numbers n such that string 5,8 occurs in the base 9 representation of n but not of n+1.at n=38A044685
- Numbers n such that string 7,5 occurs in the base 9 representation of n but not of n+1.at n=37A044700
- Numbers n such that string 0,7 occurs in the base 10 representation of n but not of n+1.at n=29A044720
- Numbers whose base-4 representation contains exactly two 2's and three 3's.at n=33A045146