6787
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 28
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 7416
- Proper Divisor Sum (Aliquot Sum)
- 629
- 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
- 6160
- Möbius Function
- 1
- Radical
- 6787
- 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
- 44
- 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 partitions into non-integral powers.at n=14A000263
- a(n) = 2^(n-1) + 2^[ n/2 ] + 2^[ (n-1)/2 ] - F(n+3).at n=14A005674
- a(n) = F(n+3) + c(n) where F(k) is k-th Fibonacci number and c(n) is n-th number that is 1 or 2 or is not a Fibonacci number.at n=16A022809
- a(n) = b(n) + d(n), where b(n) = (n-th Fibonacci number > 2) and d(n) = (n-th number that is 1 or is not a Lucas number).at n=16A023496
- a(n) = b(n) + d(n), where b(n) = (n-th Fibonacci number > 1) and d(n) = (n-th number that is 1, 2, or 3, or is not a Lucas number).at n=17A023500
- Number of partitions of n with equal number of parts congruent to each of 1, 2 and 3 (mod 5).at n=58A035578
- a(n) = Sum_{i=1..n} Sum_{j=1..i} (prime(i) - prime(j)).at n=21A062020
- a(n) = Sum_{k=1..n} Sum_{d=1..k} (k mod d).at n=49A072481
- a(n) = (9*n^2 - 3*n + 2)/2.at n=39A080855
- Number of shifted Young tableaux with height <= 3.at n=12A082395
- Members of A000124 which are multiples of 11.at n=21A083511
- a(n)=floor{square((1*n^0+1*n^1+2*n^2+4*n^3)/(1*n^0+2*n^1+1*n^2))}.at n=21A086863
- Indices of terms in the sequence 3, 1, 4, 5, 9, 14, 23, ... (A000285 prefixed with 3) which are prime numbers.at n=39A091158
- Subsequence of A107629. Consider a Gaussian prime a+bi with index k in A103431. k is in A107632 when an integer multiplier m exists such that the distance of m*norm(a+bi) to k is minimal up to k. abs(m*norm(a+bi) - k) is minimal up to k. A107633 gives the squares of the norms of these Gaussian primes, A107634 the integer multipliers m.at n=10A107632
- a(n) = Sum_{d|n} A000010(n/d) * A000045(d-1).at n=20A113166
- Numbers such that the sum of the factorials of the digits of the cube is a square.at n=26A126076
- Number of squares (of nonnegative integers) that require n binary (base-2) digits.at n=29A126726
- Right-angled numbers with an internal digit as the vertex.at n=39A135602
- a(n) is the ceiling of 2^n * (sqrt(2)-1), i.e., a(n)-1 is the number whose binary representation gives the first n bits of sqrt(2)-1.at n=13A136322
- a(n) = 8*n^2 + 2*n + 1.at n=29A188135