5128
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 9630
- Proper Divisor Sum (Aliquot Sum)
- 4502
- 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
- 2560
- Möbius Function
- 0
- Radical
- 1282
- Omega Function (Ω)
- 4
- 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
- no
- Squarefree Number
- no
- 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
- yes
- Odd
- no
Appears in sequences
- a(n) = s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n+1-k), where k = [ (n+1)/2 ], s = (composite numbers).at n=25A024588
- n written in fractional base 9/5.at n=44A024653
- s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n-k+1), where k = [ n/2 ], s = (composite numbers).at n=24A025102
- a(n) = floor(Sum_{1<=i<j<=n} (sqrt(j)-sqrt(i))^2).at n=44A025196
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 17.at n=35A031515
- Composite n such that phi(n+4) = phi(n)+4.at n=34A056773
- Positive numbers whose product of digits is 5 times their sum.at n=33A062382
- The sigma(EulerPhi)-perfect numbers, where the set of f-perfect numbers for an arithmetical function f is defined in A066218.at n=3A066226
- a(n) = (10^n + 4^n)/2.at n=4A081343
- Indices of primes in A095134(n).at n=39A095135
- The values within a cycle of length 53 of the map x->A098189(x), sorted.at n=36A098191
- Location of restriction sites for the enzyme PfeI in PhiX174 DNA.at n=10A108877
- Numbers of the form x^4 + 6*x^2*y^2 + y^4 (where x,y are positive integers).at n=22A135797
- Expansion of 1/(1 - x^3 - x^4 - x^5 + x^8)^2.at n=30A147851
- Numbers k such that binomial(3k,k) is odd and not divisible by 5.at n=47A154119
- The indexing sequence for successively better golden semiprimes.at n=16A165569
- a(n) = n*n in the arithmetic where when digits are to be added they are multiplied, and when they are to be multiplied they are added.at n=29A169921
- Number of line segments connecting exactly 3 points in an n X n grid of points.at n=15A177719
- a(n) is the sum of all pairwise Manhattan distances for optimal towns with n buildings.at n=47A193452
- Number of partitions of n such that the number of parts and the smallest part are coprime.at n=29A200928