6181
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
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 7072
- Proper Divisor Sum (Aliquot Sum)
- 891
- 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
- 5292
- Möbius Function
- 1
- Radical
- 6181
- 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
- 62
- 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
- Octahedral numbers: a(n) = n*(2*n^2 + 1)/3.at n=21A005900
- Expansion of (1+x^2)/((1-x)^2*(1-x^2)^2).at n=40A005993
- a(n) = 1*t(n) + 2*t(n-1) + ... + k*t(n+1-k), where k=floor((n+1)/2), t = A000045 (Fibonacci numbers).at n=15A023860
- a(n) = 1*t(n) + 2*t(n-1) + ... + k*t(n+1-k), where k=floor((n+1)/2) and t = (F(2), F(3), F(4), ...), F(n) = Fibonacci(n).at n=14A023864
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (natural numbers), t = (Fibonacci numbers).at n=14A024857
- Expansion of Molien series for 4-D extraspecial group 2^{1+2*2}.at n=41A030533
- Numerators of continued fraction convergents to sqrt(395).at n=4A041750
- Numbers k such that the digits of k^3 occur with the same frequency.at n=50A052047
- Numbers k such that k^3 is a cube whose digits occur with an equal minimum frequency of 2.at n=9A052051
- Numbers n such that n^2 contains exactly 8 different digits.at n=40A054036
- Coefficients of a polynomial used in calculation of A055913.at n=10A055916
- Numbers n > 13 such that x^n + x^13 + x^12 + x^11 + x^10 + x^9 + x^8 + x^7 + x^6 + x^5 + x^4 + x^3 + x^2 + x + 1 is irreducible over GF(2).at n=30A057489
- First (leftmost) digit - second digit + third digit - fourth digit .... = 12.at n=43A061881
- a(n) = (2*n - 1)*(8*n^2 - 8*n + 3)/3.at n=10A063496
- Number of potential flows in n X n array with integer velocities in -10..10, i.e., number of n X n arrays with adjacent elements differing by no more than 10, counting arrays differing by a constant only once.at n=1A068757
- a(n) = Sum_{k=1..n} antisigma(k), where antisigma(i) = sum of the nondivisors of i that are between 1 and i.at n=33A076664
- Table T(n,k) read by rows which contains in row n and column k the sum of A001055(A036035(n,j)) over all column indices j where A036035(n,j) has k distinct prime factors.at n=39A093936
- Number of distinct products of subsets of integers in the interval [n^2+1, (n+1)^2-1] which are twice a square.at n=37A099500
- For each partition of n, calculate (dM2/dM3) where dM2 = A036039(p) and dM3 = A036040(p); then sum over all partitions of n.at n=8A107107
- Numbers k such that k^6+6 is prime.at n=30A109836