9155
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 10992
- Proper Divisor Sum (Aliquot Sum)
- 1837
- 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
- 7320
- Möbius Function
- 1
- Radical
- 9155
- 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
- 153
- 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 197*2^k+1 is prime.at n=12A032475
- Multiplicity of highest weight (or singular) vectors associated with character chi_113 of Monster module.at n=43A034501
- Indices n of primes p(n), p(n+2) such that p(n)+1 and p(n+2)+1 have the same largest prime factor.at n=13A105404
- Odd nonprimes n such that n+d+1 is prime for all divisors d of n.at n=24A187554
- Numbers k such that the heptagonal number H(k) is equal to the sum of the pentagonal numbers P(m), P(m+1), P(m+2) and P(m+3) for some m.at n=1A252770
- Halogen sequence: a(n) = A018227(n)-1.at n=35A271999
- Diagonal of the rational function 1/(1 - x - y - z - x y - y z - x y z).at n=3A274780
- Number of "Euclidean primes" with respect to the first n primes.at n=16A283936
- Indices of primes followed by a gap (distance to next larger prime) of 32.at n=29A320714
- 4*a(n) is the maximum possible determinant of a 3 X 3 matrix whose entries are 9 consecutive primes starting with prime(n).at n=5A340923
- For 1<=x<=n, 1<=y<=n, write gcd(x,y) = u*x+v*y with u,v minimal; a(n) = sum of the values of |u|.at n=45A345432
- a(n) is the number of tetrapods standing on the four edges of an n X n grid, so that no two feet are the same distance apart and no foot is on a corner. Tetrapods with congruent footprints are counted only once.at n=16A353447
- a(n) = a(n-2) + 2*a(n-4) - a(n-10), with a[0..9] = [1, 1, 1, 1, 1, 2, 3, 5, 6, 9].at n=30A366143
- Semiprimes that are the sum of two successive terms of A092192.at n=42A366167
- Number of non-similar triangles possible with distinct positive integer side lengths of at most n units.at n=51A373051