13393
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 13680
- Proper Divisor Sum (Aliquot Sum)
- 287
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 13108
- Möbius Function
- 1
- Radical
- 13393
- 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
- 94
- 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
- (n - phi(n)) | sigma(n) for composite n not congruent to 2 (mod 4).at n=24A055164
- Geometric mean of the digits = 3. In other words, the product of the digits is = 3^k where k is the number of digits.at n=35A061427
- Expansion of 1/(1-2*x+x^2+x^3).at n=24A077941
- Expansion of 1 / (1 + x^2 - x^3) in powers of x.at n=51A077961
- Expansion of 1/(1 + 2*x + x^2 - x^3).at n=24A077990
- a(1)=1, a(n+1) = a(n) + spf(Sum_{i=1..n} a(i)), where spf=A020639 (smallest prime factor).at n=23A080180
- Pseudo-random numbers: gcc 2.6.3 version for 32-bit integers.at n=39A084276
- Number of partitions of n such that there is exactly one part which occurs twice, while all other parts occur only once.at n=54A090858
- Indices of primes in sequence defined by A(0) = 51, A(n) = 10*A(n-1) + 31 for n > 0.at n=15A101578
- Sum of all primes from n-th prime to (2*n-1)-th prime.at n=42A161463
- Number of nXnXn 0..6 triangular arrays with each element x equal to the number its neighbors equal to 4,1,0,1,2,0,0 for x=0,1,2,3,4,5,6.at n=4A202757
- Number of (n+1)X(1+1) 0..1 arrays x(i,j) with row sums sum{j^4*x(i,j), j=1..1+1} nondecreasing, and column sums sum{i^4*x(i,j), i=1..n+1} nondecreasing.at n=43A232790
- Expansion of F(x) where F(x) = 1 + x / (1 - x * F(x^2)^2 ).at n=17A238431
- 6-step Fibonacci sequence starting with (0,0,1,0,0,0).at n=20A251708
- G.f.: (1 + x^4 + x^5 + x^6 + x^10 + x^11 + x^12 + x^16)/Product_{i=1..8} (1 - x^i).at n=34A256975
- a(n) is the sum of quadratic nonresidues of A002145(n) (the n-th prime == 3 mod 4).at n=26A282036
- Let p = n-th prime == 3 mod 8; a(n) = sum of quadratic nonresidues mod p .at n=13A282726
- Numbers that cannot be written as a difference of 11-smooth numbers.at n=9A326319
- Irregular triangle read by rows where T(n,k) is the number of integer compositions of n with k weak excedances (parts on or above the diagonal), all zeros removed.at n=53A352525
- Products of exactly two distinct primes in A090252, in order of appearance.at n=56A354160