13727
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 16416
- Proper Divisor Sum (Aliquot Sum)
- 2689
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 11232
- Möbius Function
- -1
- Radical
- 13727
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 89
- 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) = T(n,1) + T(n-1,2) + ...+ T(n-k+1,k), where k = floor((n+1)/2) and T is the array defined in A026098.at n=40A026103
- a(n) = 10*n^2+n.at n=36A055437
- Expansion of Product_{k > 0} (1 + f(k)*x^k), where f(n) = A147952(n).at n=30A147953
- Numbers k that divide 10^(k+1)-1.at n=38A175203
- (A178476(n)-3)/9.at n=2A178486
- G.f.: (1-2*x^2)/(1-2*x-5*x^2+9*x^3).at n=10A200862
- Numbers n such that phi(sigma(n)) = sigma(n) - phi(n).at n=10A230372
- Number of nX3 0..1 arrays with every element equal to 2, 3, 4, 5 or 7 king-move adjacent elements, with upper left element zero.at n=7A298624
- T(n,k)=Number of nXk 0..1 arrays with every element equal to 2, 3, 4, 5 or 7 king-move adjacent elements, with upper left element zero.at n=47A298629
- T(n,k)=Number of nXk 0..1 arrays with every element equal to 2, 3, 4, 5 or 7 king-move adjacent elements, with upper left element zero.at n=52A298629
- Numbers k such that k and k+1 are both divisible by the total binary weight of their divisors (A093653).at n=5A338514
- a(n) is the index of the smallest square pyramidal number divisible by exactly n square pyramidal numbers.at n=17A359095
- Number k such that the periods of the continued fractions of sqrt(k) and sqrt(k+1) have the same distinct terms.at n=44A374234
- Length of n-th run of consecutive primes in A375564.at n=16A376195
- Numbers k such that k + sopfr(k) is a cube.at n=19A389862