8555
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 23
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 10800
- Proper Divisor Sum (Aliquot Sum)
- 2245
- 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
- 6496
- Möbius Function
- -1
- Radical
- 8555
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 52
- 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
- no
- Odd
- yes
Appears in sequences
- Number of positive integers <= 2^n of form x^2 + 12 y^2.at n=16A000021
- Square pyramidal numbers: a(n) = 0^2 + 1^2 + 2^2 + ... + n^2 = n*(n+1)*(2*n+1)/6.at n=29A000330
- a(n) = floor(n*(n-1)*(n-2)/24).at n=60A011842
- Odd square pyramidal numbers.at n=14A015221
- Cycle class sequence c(n) (the number of true cycles of length n in which a certain node is included) for zeolite MFI = ZSM-5 Nan[AlnSi96-nO192] starting with a T3 atom.at n=12A019160
- a(n) = s(1)*s(n) + s(2)*s(n-1) + ... + s(k)*s(n+1-k), where k = floor((n+1)/2), s = (odd natural numbers).at n=28A024598
- Denominator of Bernoulli(2n+2) - Bernoulli(2n).at n=28A029763
- Scan decimal expansion of Pi until all n-digit strings have been seen; a(n) is number of digits that must be scanned.at n=2A036903
- Numbers having three 5's in base 10.at n=34A043511
- a(n) = Sum{a(k): k=0,1,2,...,n-3,n-1}; a(n-2) is not a summand; 2 initial terms required.at n=16A049855
- Record subsequence of b(3k+1), b()=A048142().at n=29A051057
- 23-gonal numbers: a(n) = n(21n-19)/2.at n=29A051875
- Consider the line segment in R^n from the origin to the point P=(1,2,3,...,n); let d = squared distance to this line from the closest point of Z^n (excluding the endpoints). Sequence gives d times P.P.at n=28A059774
- Square spiral sequence: numbers are placed in a square spiral, a(1)=1, a(n) is found as the sum of the row (in the previous direction) a(n-1) is in.at n=23A062410
- a(n) = Sum_{d|n} sigma(d)^2.at n=43A065018
- Square root of sum defined in A007475(n) and A001032(n).at n=21A076215
- a(n) = (1/24)*(sigma_3(2*n-1) - sigma_1(2*n-1)).at n=29A081861
- Least area/6 of primitive Pythagorean triangles with odd leg 2n+1.at n=28A096893
- Structured rhombic dodecahedral numbers (vertex structure 9).at n=14A100157
- Sequence and first differences include all square numbers exactly once.at n=28A109678