6901
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 7072
- Proper Divisor Sum (Aliquot Sum)
- 171
- 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
- 6732
- Möbius Function
- 1
- Radical
- 6901
- 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
- Fibonacci sequence beginning 1, 29.at n=13A022399
- s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = A000201 (lower Wythoff sequence), t = A001950 (upper Wythoff sequence).at n=25A025119
- a(n) = (2*n - 1)*(3*n + 1).at n=34A033569
- Numerators of continued fraction convergents to sqrt(346).at n=7A041654
- Denominators of continued fraction convergents to sqrt(587).at n=11A042125
- T(2n-1,n), array T as in A054134.at n=5A054141
- a(n) = n*coefficient of x^n in log(1+S), S = g.f. for A000084.at n=8A058757
- Centered 23-gonal numbers.at n=24A069174
- Least x = a(n) such that sum of common prime divisors (without multiplicity) of sigma(x) and phi(x) equals n, or 0 if such number (apparently) does not exist.at n=18A082056
- Least x=a(n) such that product of common prime-divisors [without multiplicity] of sigma(x) and phi(x) equals n; or 0 if n is not a squarefree number or if no such x exists. Among indices n only squarefree numbers arise because multiplicity of prime factors is ignored.at n=33A082057
- Numbers k such that the k-th semiprime == 10 (mod k).at n=12A106135
- Let T(S,Q) be the sequence obtaining by starting with S and repeatedly reversing the digits and adding Q to get the next term. This is T(1016,5), the first S for which T(S,5) reaches a cycle of length 36.at n=34A118879
- E.g.f.: A(x) = exp(x + A(x)^2) - 1.at n=4A143139
- a(1) = 1; thereafter a(n) is always the smallest integer > a(n-1) not leading to a contradiction, such that any six consecutive digits in the sequence sum up to a prime.at n=23A152606
- a(n) = 1 + n*(n+1)*(n-1)/2.at n=24A158842
- Number of permutations of length n which avoid the patterns 1234 and 2341.at n=8A165540
- a(n) = ceiling(A107293(n)/2).at n=31A173693
- Squarefree semiprimes k such that (m+1)^2-k is also a square, where m = ceiling(sqrt(k)).at n=32A180656
- Upper s-Wythoff sequence, where s=A081276 (eighth cubes). Complement of A184431.at n=36A184432
- Number of -3..3 arrays x(i) of n+1 elements i=1..n+1 with set{t,u,v in 0,1}((x[i+t]+x[j+u]+x[k+v])*(-1)^(t+u+v)) having one, two, three, four, six or seven distinct values for every i,j,k<=n.at n=4A211741