3855
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 6192
- Proper Divisor Sum (Aliquot Sum)
- 2337
- 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
- 2048
- Möbius Function
- -1
- Radical
- 3855
- 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
- 51
- 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 n-bead necklaces with beads of 2 colors and primitive period n, when turning over is not allowed but the two colors can be interchanged.at n=17A000048
- Lerch's function q_2(n) = (2^{phi(t)} - 1)/t where t = 2*n - 1.at n=8A001226
- Sierpiński's triangle (Pascal's triangle mod 2) converted to decimal.at n=11A001317
- Divisors of 2^16 - 1.at n=11A003527
- Divisors of 2^32 - 1 (for a(1) to a(31), the 31 regular polygons with an odd number of sides constructible with ruler and compass).at n=11A004729
- a(n) = floor(2^(n-1)/n).at n=16A006788
- Fermat quotients: (2^(p-1)-1)/p, where p=prime(n).at n=5A007663
- Expansion of (1+x^2)(1+x^4)/((1-x)^2*(1-x^2)*(1-x^3)).at n=32A007979
- Coordination sequence T3 for Zeolite Code AET.at n=43A008009
- Coordination sequence T3 for Zeolite Code FER.at n=38A008108
- Coordination sequence T2 for Zeolite Code LTN.at n=43A008141
- Coordination sequence T4 for Zeolite Code MOR.at n=40A008185
- Prefix (or Levenshtein) codes for natural numbers.at n=31A010097
- Least k such that (2*p_n)*k + 1 | Mersenne(p_n), p_n = n-th prime, n >= 2.at n=5A016048
- Coordination sequence T2 for Zeolite Code CGF.at n=43A019452
- Sequence satisfies T^2(a)=a, where T is defined below.at n=44A027588
- Numbers having period-1 7-digitized sequences.at n=24A031201
- Every run of digits of n in base 4 has length 2.at n=32A033002
- Number of partitions of n into parts not of the form 9k, 9k+2 or 9k-2. Also number of partitions with 1 part of size 1 and differences between parts at distance 3 are greater than 1.at n=38A035941
- Bisection of A001317.at n=5A038192