5555
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- yes
- Repdigit
- yes
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 7344
- Proper Divisor Sum (Aliquot Sum)
- 1789
- 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
- 4000
- Möbius Function
- -1
- Radical
- 5555
- 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
- 129
- 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
- a(n) = 5*(10^n - 1)/9.at n=4A002279
- Numbers that are the sum of 4 positive 6th powers.at n=22A003360
- Coordination sequence T4 for Zeolite Code TON.at n=46A008244
- Coordination sequence T1 for Milarite.at n=46A008256
- Repdigit numbers, or numbers whose digits are all equal.at n=32A010785
- Numbers > 9 with all digits the same.at n=22A014181
- Powers of fourth root of 23 rounded down.at n=11A018111
- a(n) = n*(23*n - 1)/2.at n=22A022280
- a(n) = Sum_{i=1..floor((n+1)/4)} a(2*i-1) * a(n-2*i+1), with a(1)=a(2)=1 and a(3)=5.at n=13A024729
- a(n) = Sum_{k = 1..n} k*floor((n + prime(k))/k).at n=44A024929
- a(n) = Sum_{i=1..floor((n+2)/4)} a(2i-1)*a(n-2i+1), with a(1)=a(2)=1 and a(3)=5.at n=12A024951
- Number of distinct products i*j with 0 <= i, j <= n-th prime.at n=33A027419
- Palindromes of form k^2 + k + 5.at n=6A027728
- Numbers whose maximal base-10 run length is 4.at n=4A033285
- a(n) = floor(10^5/n).at n=17A033427
- Decimal part of a(n)^(1/3) starts with reversal of its integer part: first term of runs.at n=15A034309
- Numerators of continued fraction convergents to sqrt(317).at n=6A041598
- Numbers that are palindromic and divisible by 5.at n=18A043040
- Numbers having four 5's in base 10.at n=0A043512
- Palindromes with exactly 3 prime factors (counted with multiplicity).at n=38A046329