7785
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 27
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 13572
- Proper Divisor Sum (Aliquot Sum)
- 5787
- 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
- 4128
- Möbius Function
- 0
- Radical
- 2595
- Omega Function (Ω)
- 4
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 220
- 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
- Expansion of log(1+x)*cos(sinh(x)).at n=9A009407
- Number of terms in 7th derivative of a function composed with itself n times.at n=8A022817
- Number of terms in n-th derivative of a function composed with itself 9 times.at n=7A024209
- Numbers k such that the sum of the first k primes is a square.at n=3A033997
- Number of labeled rooted trees with 3-colored leaves.at n=4A038050
- Matrix 9th power of partition triangle A008284.at n=21A050303
- Numbers k such that 3*2^k + 35 is prime.at n=44A059759
- Numbers k such that the Lucas Aurifeuillian primitive part B of Lucas(k) is prime.at n=51A061443
- Numbers equal to a permutation (or rearrangement) of the digits of the sum of their proper divisors. Rearrangements which cause leading zeros are excluded.at n=11A085844
- Sum of digits of numbers between 0 and (6/9)*(10^n-1).at n=3A089907
- a(0)=1, a(1)=1, a(n) = 9*a(n/2) for even n >= 2, and a(n) = 8*a((n-1)/2) + a((n+1)/2) for odd n >= 3.at n=22A116526
- Odd integers that do not generate monotonically decreasing infinitary aliquot sequences.at n=19A127667
- Sum of a positive square and a positive cube in at least three ways.at n=12A171385
- Numbers m such that (6*m)^5 is a sum of a twin prime pair.at n=35A173560
- Numbers k such that Sum_(i=1..k) prime(i)*(-1)^(i+1) is a square.at n=14A175117
- Numbers n such that Mordell's equation y^2 = x^3 + n has exactly 16 integral solutions.at n=10A179157
- Number of ordered 9-tuples of distinct pairwise coprime positive integers with largest element n.at n=27A186980
- Number of 0..2 arrays x(0..n-1) of n elements with zero n-1st difference.at n=15A200148
- Number of n X n 0..3 arrays with every nonzero element less than or equal to some NW, E or S neighbor.at n=2A203390
- Number of nX3 0..3 arrays with every nonzero element less than or equal to some NW, E or S neighbor.at n=2A203392