12846
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 5
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 25704
- Proper Divisor Sum (Aliquot Sum)
- 12858
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- yes
Derived Values
- Euler's Totient
- 4280
- Möbius Function
- -1
- Radical
- 12846
- 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
- 125
- 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
- a(0) = a(1) = 1; thereafter a(n) = sigma(a(n-1)) + sigma(a(n-2)).at n=12A000458
- Triangle read by rows: T(n,k) = number of permutations of length n with exactly k rising or falling successions, for n >= 1, 0 <= k <= n-1.at n=30A001100
- a(0) = 1, a(n) = 19*n^2 + 2 for n>0.at n=26A010009
- a(n) = 2^n - A056045(n).at n=13A056200
- Numbers which are the sum of their proper divisors containing the digit 4.at n=19A059463
- Numbers n such that sigma(phi(n)) = sum of anti-divisors of n.at n=3A074835
- Arrange n^2 octagons that each have area 7 so that they leave (n-1)^2 square gaps each with area 2; a(n) is the total area of these polygons.at n=37A086640
- Number of permutations of length n with exactly 2 rising or falling successions.at n=8A086853
- Row sums of triangle A134141 (S1p(7)).at n=5A132164
- Number of arrays of 4 nondecreasing integers in -n..n with sum zero and equal numbers greater than zero and less than zero.at n=41A203292
- Numbers k whose decimal expansion can be split into at least two parts whose binary equivalents can be concatenated (in the same order) to form the binary expansion of the original number k.at n=26A237041
- Coordination sequence for (3,3,6) tiling of hyperbolic plane.at n=19A265073
- Square array A(i,j), i >= 0, j >= 0, read by antidiagonals: A(i,j) = Sum_{|X|=0..i} Sum_{|Y|=0..i} Product_{k=1..j} (1+X(k)+Y(k)), where X and Y are multi-indices of length j.at n=47A358628
- Positions of records in A366091.at n=44A366065