12381
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 16512
- Proper Divisor Sum (Aliquot Sum)
- 4131
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8252
- Möbius Function
- 1
- Radical
- 12381
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 37
- 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
- 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 74.at n=26A031572
- Number of partitions of n into parts not of the form 17k, 17k+6 or 17k-6. Also number of partitions with at most 5 parts of size 1 and differences between parts at distance 7 are greater than 1.at n=36A035967
- Partial sums of A045618.at n=8A045889
- Discriminants of real quadratic fields with class number 1 and related continued fraction period length of 12.at n=29A050961
- Triangle T, read by rows, such that T(n,k) equals the (n-k)-th row sum of T^k, where T^k is the k-th power of T as a lower triangular matrix.at n=60A091351
- Triangle, read by rows, such that T(n,k) equals the k-th term of the convolution of the (n-1)-th diagonal with the k-th row of this triangle.at n=60A098446
- Semiprimes in A103372.at n=15A103392
- Triangle read by rows: T(n,k) is the number of nondecreasing Dyck paths of semilength n, having k distinct valley levels (n>=1, k>=0).at n=43A121463
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (-1, 1, 0), (0, 0, -1), (0, 0, 1), (1, 0, 0)}.at n=8A150055
- Triangle read by rows, binomial transform of A122196.at n=44A152230
- Number of 8 X n binary arrays without the pattern 0 1 diagonally, vertically, antidiagonally or horizontally.at n=12A188559
- Number of isosceles triangles, distinct up to congruence, on a centered hexagonal grid of size n.at n=46A241237
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 73", based on the 5-celled von Neumann neighborhood.at n=25A270089
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 73", based on the 5-celled von Neumann neighborhood.at n=26A270089
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 397", based on the 5-celled von Neumann neighborhood.at n=25A271691
- Expansion of Product_{k>0} (1 + Sum_{m>=0} x^(k*2^m)).at n=41A304393
- Expansion of Sum_{k>=1} phi(k) * x^k/(1 - x^k)^4, where phi = Euler totient function (A000010).at n=40A309323
- a(n) = (n^3 + 6*n^2 + 17*n + 6)/6.at n=40A341209
- G.f. A(x) = Sum_{n>=0} a(n)*x^n satisfies: [Sum_{n>=0} x^n/(1 - x^(n+1))]^3 = Sum_{n>=0} a(n)*x^n/(1 - x^(n+1))^3.at n=32A341374
- Number of positive solutions to (x_1)^2 + (x_2)^2 + (x_3)^2 + (x_4)^2 <= n^2.at n=13A341423