11555
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 13872
- Proper Divisor Sum (Aliquot Sum)
- 2317
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 9240
- Möbius Function
- 1
- Radical
- 11555
- 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
- 143
- 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
- a(n) = floor(n*phi^18), where phi is the golden ratio, A001622.at n=2A004933
- a(n) = a(n-1) + a(n-2) + 1 for n > 1, a(0)=1, a(1)=5.at n=17A022319
- Numbers with all odd digits, in which each digit divides the number formed by the rest, i.e., the number obtained by just removing this digit.at n=45A061507
- (prime(n)*(prime(n+1)-1) + (prime(n)-1)*prime(n+1)) / 2.at n=26A099909
- Semiprimes (A001358) made of nontrivial runs of identical digits.at n=23A116063
- Odd winning positions in Fibonacci nim.at n=22A120904
- a(0) = a(1) = 1. a(n) = a(n-1) + a(n - b(n)), where b(n) is smallest prime dividing n.at n=24A137808
- a(n) = A014217(n+3) - A014217(n).at n=17A153263
- a(n) = ((2+sqrt(3))*(4+sqrt(3))^n + (2-sqrt(3))*(4-sqrt(3))^n)/2.at n=5A162274
- Number of strings of numbers x(i=1..7) in 0..n with sum i^2*x(i)^3 equal to 49*n^3.at n=27A184322
- Expansion of g.f. 5*(1-x-x^2)/((1+x)*(1-3*x+x^2)).at n=9A189316
- Number of partitions of n such that some part is a sum of two or more other parts.at n=34A237668
- Numbers using only digits 1 and 5.at n=37A276037
- Number of 2 X n 0..1 arrays with no element equal to a strict majority of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.at n=12A279978
- Semiprime numbers whose digit string can be partitioned into three parts such that the product of the first two parts equals the third part.at n=21A280636
- Numbers that contain exactly one pair of identical digits x and a triple of identical digits y (x not equal y).at n=29A291312
- Number of n X 3 0..1 arrays with every element equal to 0, 2, 3, 5, 6, 7 or 8 king-move adjacent elements, with upper left element zero.at n=10A300091
- Number of conjugacy classes for a non-abelian group of order p^3, where p is prime: a(n) = p^2 + p - 1 where p = prime(n).at n=27A319597
- Numbers that are the sum of six fourth powers in four or more ways.at n=8A345561
- Numbers that are the sum of six fourth powers in exactly four ways.at n=8A345816