7685
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 26
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 9720
- Proper Divisor Sum (Aliquot Sum)
- 2035
- 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
- 5824
- Möbius Function
- -1
- Radical
- 7685
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 145
- 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
- Number of necklaces with n beads of 2 colors, allowing turning over (these are also called bracelets).at n=18A000029
- For any circular arrangement of 0..n-1, let S = sum of squares of every sum of two contiguous numbers; then a(n) = # of distinct values of S.at n=35A007773
- Dying rabbits: a(n) = a(n-1) + a(n-2) - a(n-6).at n=22A023436
- Least k>1 such that reverse of first n terms of A022303 repeats beginning at k-th term.at n=48A025520
- a(n) = (d(n)-r(n))/2, where d = A026049 and r is the periodic sequence with fundamental period (1,0,0,1).at n=31A026050
- a(n) = Sum_{k=n+1..2*n} T(n, k), T given by A027023.at n=8A027045
- a(n) = (1/6)*(2*n - 3)*(n + 2)*(n + 1).at n=30A058373
- Numbers of the form (10*a + b)^2 + (10*b + a)^2 with a and b less than 10, in numerical order.at n=34A061191
- a(n) = Sum_{d|n} sigma(n*d).at n=43A069546
- Expansion of (1-x)^(-1)/(1+2*x+x^3).at n=12A077926
- a(n) = 4*n^5 + 10*n^4 + 13*n^3 + 11*n^2 + 5*n + 1.at n=4A094201
- Numbers m that are the hypotenuse of exactly 13 distinct integer-sided right triangles, i.e., m^2 can be written as a sum of two squares in 13 ways.at n=38A097102
- Expansion of 1/sqrt((1-x)^2-8x^3).at n=11A098480
- a(1)=1. a(n) = a(n-1) + sum of the squares which are among the first (n-1) terms of the sequence.at n=32A101135
- a(n) = 8*n^2 - 3.at n=30A108928
- Numbers whose anti-divisors sum to a perfect cube.at n=15A109351
- a(n) = Sum_{m=1..n-1} floor(m(n-2)/2)^2.at n=11A125849
- Let f(k) = exp(Pi*sqrt(k)); sequence gives numbers k such that ceiling(f(k)) - f(k) < 1/10^3.at n=19A127022
- Row sums of triangle in A133644.at n=6A133222
- Composite numbers such that the square mean of their prime factors is a nonprime integer (where the prime factors are taken with multiplicity and the square mean of c and d is sqrt((c^2+d^2)/2)).at n=27A134602