5545
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 6660
- Proper Divisor Sum (Aliquot Sum)
- 1115
- 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
- 4432
- Möbius Function
- 1
- Radical
- 5545
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 54
- 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
- Euler transform of A000292.at n=8A000335
- Number of centered 3-valent (or boron, or binary) trees with n nodes.at n=18A000675
- If F(n) is the n-th Fibonacci number, then a(2n) = (F(2n+1) + F(n+2))/2 and a(2n+1) = (F(2n+2) + F(n+1))/2.at n=19A001224
- a(n) = (F(2*n-1) + F(n+1))/2 where F(n) is a Fibonacci number.at n=11A005207
- Coordination sequence T1 for Zeolite Code BIK.at n=45A008047
- Coordination sequence T3 for Zeolite Code TON.at n=46A008243
- Triangle of Mahonian numbers T(n,k): coefficients in expansion of Product_{i=0..n-1} (1 + x + ... + x^i), where k ranges from 0 to A000217(n-1). Also enumerates permutations by their major index.at n=101A008302
- Triangle of Mahonian numbers T(n,k): coefficients in expansion of Product_{i=0..n-1} (1 + x + ... + x^i), where k ranges from 0 to A000217(n-1). Also enumerates permutations by their major index.at n=119A008302
- Numbers k such that the continued fraction for sqrt(k) has period 27.at n=20A020366
- Pisot sequence P(5,11), a(0)=5, a(1)=11, a(n+1) is the nearest integer to a(n)^2/a(n-1).at n=9A021008
- Fibonacci sequence beginning 1, 5.at n=16A022095
- a(n) = (d(n)-r(n))/5, where d = A026063 and r is the periodic sequence with fundamental period (1,4,0,0,0).at n=44A026065
- Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted then there are a pair of central terms both equal to 7.at n=14A031420
- Numbers k such that 209*2^k+1 is prime.at n=14A032481
- Numbers having three 5's in base 10.at n=14A043511
- Numbers whose base-4 representation contains exactly four 1's and three 2's.at n=3A045108
- a(n) = 3*a(n-1) - a(n-2), a(0)=1, a(1)=6.at n=8A054492
- a(n+1) is smallest number with a(n+1)^n > a(n)^(n+1).at n=19A059923
- Number of distinct ways to tile a 2 X n rectangle with dominoes (solutions are identified if they are rotations or reflections of each other).at n=19A060312
- Number of incongruent ways to tile a 3 X 2n room with 1x2 Tatami mats. At most 3 Tatami mats may meet at a point.at n=19A068928