6856
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 25
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 12870
- Proper Divisor Sum (Aliquot Sum)
- 6014
- 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
- 3424
- Möbius Function
- 0
- Radical
- 1714
- Omega Function (Ω)
- 4
- 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
- 31
- 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
- yes
- Odd
- no
Appears in sequences
- a(n) = floor( n*(n-1)*(n-2)/27 ).at n=58A011909
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = (composite numbers), t = (primes).at n=21A024604
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 41.at n=23A031539
- Number of partitions of n with equal nonzero number of parts congruent to each of 0 and 2 (mod 5).at n=43A035563
- Sets of 4 consecutive numbers with equal number of divisors.at n=19A039665
- Nonnegative numbers of the form n^3 (+/-) 3, n >= 0.at n=36A052276
- Let f(n) be 2n + POD(n) + 1 if n is even, otherwise 2n - POD(n) - 1, where POD(n) is the product of digits of n. Sequence gives smallest number requiring n iterations to reach a prime.at n=31A074808
- Sum of odd-indexed primes.at n=38A077131
- Indices of primes in sequence defined by A(0) = 63, A(n) = 10*A(n-1) + 13 for n > 0.at n=18A101528
- Numbers with composite sum of digits and prime sum of cubes of digits.at n=32A121642
- Triangle related to super-Catalan numbers (or little Schroeder numbers).at n=40A130743
- Triangle read by rows: T(n,m) is the number of cyclic permutations of [n] in which m of successive numbers add to a prime. 0<=m<=n, read by rows n>=0.at n=56A132178
- a(n) = 2*A000984(n) - (n+1).at n=7A134759
- Number of compositions of n into floor((3*j)/2) kinds of j's for all j>=1.at n=9A143787
- a(n) = 4*a(n-1) - 2*a(n-2) for n > 1; a(0) = 3, a(1) = 14.at n=6A164304
- Triangle read by rows, A084938 * A165489 diagonalized as an infinite lower triangular matrix.at n=48A165490
- Integers n such that 4*prime(n)-+3 are nonconsecutive primes.at n=35A173487
- n^3+Smallest square, (Smallest square >= n^3).at n=15A176581
- Parameters n for which the elliptic curve y^2=x^3+n has rank 4.at n=4A179124
- Numbers n such that Mordell's equation y^2 = x^3 + n has exactly 12 integral solutions.at n=14A179154