6993
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
- 3
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 12160
- Proper Divisor Sum (Aliquot Sum)
- 5167
- 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
- 3888
- Möbius Function
- 0
- Radical
- 777
- Omega Function (Ω)
- 5
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 106
- 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
- Number of positive integers <= 2^n of form x^2 + 3 y^2.at n=15A000205
- From solution to a difference equation.at n=5A005923
- Expansion of e.g.f.: exp(arcsin(arcsinh(x)))=1+x+1/2!*x^2+1/3!*x^3+1/4!*x^4+9/5!*x^5...at n=9A012111
- sinh(arcsin(arcsinh(x)))=x+1/3!*x^3+9/5!*x^5+113/7!*x^7+6993/9!*x^9...at n=4A012116
- sech(arctanh(x)*cos(x))=1-1/2!*x^2+9/4!*x^4-225/6!*x^6+6993/8!*x^8...at n=4A012749
- Expansion of e.g.f. exp(sec(x)*arcsinh(x)).at n=8A012821
- cosh(sec(x)*arcsinh(x))=1+1/2!*x^2+9/4!*x^4+225/6!*x^6+6993/8!*x^8...at n=4A012831
- Apply partial sum operator twice to factorials.at n=8A014144
- Numbers k that divide s(k), where s(1)=1, s(j)=7*s(j-1)+j.at n=37A014854
- Position of n^3 + 9 in A024975.at n=39A024979
- Divisors of 999999.at n=46A027892
- a(n+1) is the smallest odd m whose cototient equals a(n).at n=10A063830
- a(n) = n^4*(n^4-1)/240.at n=6A078876
- Number of triangular partitions of n of order 3.at n=26A084439
- a(n) = 7*(10^n - 1).at n=3A086578
- Expansion of x^2/((1-x)*(1+2*x)*(1-6*x)).at n=7A091056
- Numbers n such that 9*10^n + 3*R_n + 4 is prime, where R_n = 11...1 is the repunit (A002275) of length n.at n=22A103096
- Coefficients of Pi^(2*n+1) in a certain integer relation involving Ramanujan exponential-type sums.at n=1A119541
- Numbers n such that every digit occurs at least once in n^3.at n=21A119735
- a(n) = 16 + floor(Sum_{j=1..n-1} a(j)/2).at n=15A120142