6617
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
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 7140
- Proper Divisor Sum (Aliquot Sum)
- 523
- 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
- 6096
- Möbius Function
- 1
- Radical
- 6617
- 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
- Numerator of the n-th harmonic number H(n) divided by (n+1); a(n) = A001008(n) / ((n+1)*A002805(n)).at n=11A002547
- Number of partitions of n into Fibonacci parts (with 2 types of 1).at n=34A007000
- a(0) = 1, a(n) = 15*n^2 + 2 for n>0.at n=21A010005
- cos(arcsinh(x)*exp(x))=1-1/2!*x^2-6/3!*x^3-19/4!*x^4-20/5!*x^5...at n=8A012589
- Numbers k such that the continued fraction for sqrt(k) has period 27.at n=27A020366
- Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted then there are a pair of central terms both equal to 5.at n=33A031418
- Number of partitions in parts not of the form 19k, 19k+1 or 19k-1. Also number of partitions with no part of size 1 and differences between parts at distance 8 are greater than 1.at n=40A035970
- Number of partitions satisfying cn(2,5) < cn(1,5) + cn(4,5) and cn(3,5) < cn(1,5) + cn(4,5).at n=32A039889
- a(d-2) is the smallest member of A046076 containing an undulating sequence of 010... or 101... of maximal length d=3, 4, ...at n=4A046077
- Numbers k such that k! - (k-1)! + 1 is prime.at n=18A049432
- Numbers k such that 281*2^k + 1 is prime.at n=18A053357
- a(n) = (1/12)*(n+1)*(n^3+19*n^2+118*n+228).at n=13A092327
- Numbers k such that k*(k+6) gives the concatenation of two numbers m and m+9.at n=1A116352
- Sum of proper divisors minus the number of proper divisors of pentagonal number A000326(n).at n=47A152986
- a(n) = 7*n*(n+1)/2 - 5.at n=42A166154
- a(n) = A175369(n^2).at n=12A175370
- Numbers k such that k^p+p is prime, where p is product of the digits of k.at n=2A178327
- Triangle of coefficients of polynomials u(n,x) jointly generated with A208339; see the Formula section.at n=52A209152
- 18k^2-12k-7 interleaved with 18k^2+6k+5 for k>=0.at n=39A216853
- Absolute difference between sum of odd divisors of n^2 and sum of even divisors of n^2.at n=47A224339