13493
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
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 13728
- Proper Divisor Sum (Aliquot Sum)
- 235
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 13260
- Möbius Function
- 1
- Radical
- 13493
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 45
- 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
- Numbers n such that sigma (phi ( n ) ) = sigma (sigma (n ) ) where phi is Euler's totient and sigma is the multiplicative sum-of-divisors function.at n=10A065556
- Satisfies a(n)/A079159(n) = p_n, the n-th prime (n>0), a(0)=1.at n=32A079161
- Indices of primes in sequence defined by A(0) = 71, A(n) = 10*A(n-1) - 9 for n > 0.at n=19A101128
- Number of strings of numbers x(i=1..7) in 0..n with sum i^3*x(i) equal to 343*n.at n=11A184262
- Constant term of the reduction by x^2 -> x+1 of the polynomial p(n,x) defined at Comments.at n=16A192960
- a(n) = 2^n mod n^3.at n=34A233442
- Positions of 3's in A234323.at n=20A234804
- Sequence of pairwise relatively prime numbers of class P_8 (see comment in A275246).at n=13A275253
- a(n) = a(n-1) + 3*a(n-2) -2*a(n-3) - 2*a(n-4), where a(0) = 1, a(1) = -1, a(2) = -1, a(3) = 2.at n=19A295737
- Numbers k such that there is no prime p and index j > k such that A002182(j) = p * A002182(k).at n=4A309042
- Integers k for which A000594(k)^2 > 4 k^11, where A000594 is Ramanujan's tau function.at n=30A364087
- Expansion of 1/(1 - x/(1 - 8*x^2)^(1/4)).at n=12A371927