8615
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 10344
- Proper Divisor Sum (Aliquot Sum)
- 1729
- 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
- 6888
- Möbius Function
- 1
- Radical
- 8615
- 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
- 78
- 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
- a(n) = dot_product(1,2,...,n)*(3,4,...,n,1,2).at n=27A026037
- a(n) = least k such that 1+2+...+k >= E{1,2,...,n}, where E is the 3rd elementary symmetric function.at n=32A027917
- Digitally balanced numbers in both bases 2 and 3.at n=17A049361
- Number of primes less than 10^n with initial digit 5.at n=5A073513
- a(n)=A074639(A074647(n)).at n=35A074648
- Floor(n^3/8).at n=41A081276
- a(1) = 1, otherwise a(n) = floor(Pi^(n+1)/(Pi^2 + 1)).at n=9A090426
- a(n) is the largest number such that all of a(n)'s length-n substrings are distinct and divisible by 41.at n=2A093241
- Matrix inverse of triangle A104559, read by rows.at n=40A104560
- n^3 - 1 divided by its largest cube divisor.at n=39A128972
- Numbers k that divide the sum of the first k nonprimes.at n=7A129749
- Number of up/down (or down/up) compositions of n into distinct parts.at n=33A129838
- Similar to A072921 but starting with 5.at n=39A152234
- Numbers n such that 8*n+1 is a cube.at n=5A165220
- Diagonal sums of the Riordan matrix (g(x),x*g(x)), where g(x) = (1-x-sqrt(1-2*x-3*x^2-4*x^3))/(2*x^2*(1+x)) (A190252).at n=10A190255
- Monotonic ordering of nonnegative differences 7^i-2^j, for 40>=i>=0, j>=0.at n=32A192119
- Coefficients of auxiliary tree counting function S_{1,1}(x).at n=7A196471
- Numbers whose Schwarzian arithmetic derivative is an integer.at n=20A209872
- Triangle read by rows: T(n,k) is the number of ascent sequences of length n with last occurrence of the maximal value at position k-1.at n=43A218581
- a(n) = floor((n + 1/2)^3).at n=20A219085