8781
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 24
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 11712
- Proper Divisor Sum (Aliquot Sum)
- 2931
- 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
- 5852
- Möbius Function
- 1
- Radical
- 8781
- 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
- 140
- 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
- Not integral, withdrawn.at n=7A002693
- Define the sequence S(a(0),a(1)) by a(n+2) is the least integer such that a(n+2)/a(n+1) > a(n+1)/a(n) for n >= 0. This is S(1,6).at n=5A018904
- 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 62.at n=28A031560
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 48 ones.at n=29A031816
- Number of polyominoids containing n squares: these are 2-dimensional polyominoes in a three-dimensional grid (edge-connected squares, like the floors, ceilings and walls of a building). Mirror images are distinguished.at n=5A056846
- a(n) = floor( n^Pi ).at n=17A061294
- Triangle read by rows: T(n,k) (n,k>=0) = number of peakless Motzkin paths of length n having k valleys (i.e., (1,-1) followed by (1,1)) at level zero (can be easily translated into RNA secondary structure terminology).at n=45A110333
- Semiprimes s such that s-/+2 are primes.at n=40A125215
- Numbers k with property that 19*k + {2,4,8,10} are two pairs of consecutive twin primes.at n=4A152926
- Riordan array (f(x), x*f(x)) where f(x) is the g.f. of A064613.at n=30A171568
- Apply partial sum operator 4 times to primes.at n=11A178138
- Total number of smallest parts in all partitions of n that do not contain 1 as a part.at n=35A195820
- Number of n X n 0..4 arrays with each element x equal to the number of its horizontal and vertical neighbors equal to 1,2,3,0,4 for x=0,1,2,3,4.at n=4A196572
- Number of nX5 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 1,2,3,0,4 for x=0,1,2,3,4.at n=4A196575
- T(n,k)=Number of nXk 0..4 arrays with each element x equal to the number of its horizontal and vertical neighbors equal to 1,2,3,0,4 for x=0,1,2,3,4.at n=40A196578
- Triangle read by rows, giving antidiagonals of an array of sequences representing the number of compositions of n when there are N types of ones (the sequences in the array begin (1, N, ...)).at n=60A228352
- Number of partitions p of n such that max(p) - min(p) is a part of p.at n=40A238493
- Numbers that end in (..., 128, 128, 128, ...) under the rule: next term = product of the last four digits in the sequence so far.at n=39A240967
- Main diagonal of Unlucky array: a(n) = A255543(n,n).at n=18A255549
- Number of (n+2) X (2+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00010101 00101011 or 01010101.at n=9A260921