3890
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
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 7020
- Proper Divisor Sum (Aliquot Sum)
- 3130
- 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
- 1552
- Möbius Function
- -1
- Radical
- 3890
- 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
- 38
- 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
- yes
- Odd
- no
Appears in sequences
- Number of points on surface of hexagonal prism: 12*n^2 + 2 for n > 0 (coordination sequence for W(2)).at n=18A005914
- Number of points on surface of square pyramid: 3*n^2 + 2 (n>0).at n=36A005918
- Oscillates under partition transform.at n=49A007212
- Coordination sequence T2 for Zeolite Code ATS.at n=45A008039
- Coordination sequence T2 for Zeolite Code SGT.at n=39A008230
- Coordination sequence T4 for Zeolite Code CON.at n=44A009871
- Coordination sequence T4 for Zeolite Code RUT.at n=41A009900
- a(0) = 1, a(n) = 27*n^2 + 2 for n>0.at n=12A010017
- Numbers k such that the continued fraction for sqrt(k) has period 7.at n=29A010338
- Expansion of 1/((1-x)*(1-5*x)*(1-7*x)*(1-9*x)).at n=3A022453
- Numbers k such that Fibonacci(k) == 55 (mod k).at n=48A023181
- a(n) = (d(n)-r(n))/2, where d = A026066 and r is the periodic sequence with fundamental period (1,0,0,0).at n=24A026067
- a(n) = A027170(2n-1, n-1).at n=5A027175
- a(n) = A027170(n, floor(n/2)).at n=11A027177
- a(n) = n-th largest even number in array T given by A027170.at n=50A027183
- Sequence satisfies T^2(a)=a, where T is defined below.at n=49A027595
- Number of partitions of n into parts not of form 4k+2, 24k, 24k+5 or 24k-5. Also number of partitions in which no odd part is repeated, with at most 2 parts of size less than or equal to 2 and where differences between parts at distance 5 are greater than 1 when the smallest part is odd and greater than 2 when the smallest part is even.at n=42A036031
- Row/column pre-periods of Sprague-Grundy values of Wythoff's Game.at n=30A046874
- Numbers n such that n | 4^n + 3^n + 2^n + 1^n.at n=24A056643
- a(n) = Sum_{k=1..n} phi(k)^2.at n=29A057434