13111
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 7
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 14992
- Proper Divisor Sum (Aliquot Sum)
- 1881
- 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
- 13111
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 50
- 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
- a(n) = Sum_{k=1..n} k*phi(k).at n=39A011755
- Numbers having only digits 1 and 3 in their decimal representation.at n=38A032917
- a(n) = a(n-1)+ a(round(2*(n-1)/3)) +a(round((n-1)/3)) starting a(1)=1.at n=32A033498
- Numbers with multiplicative digital root value 3.at n=13A034050
- Numbers having four 1's in base 10.at n=30A043496
- Numbers n such that sum of digits and product of digits are both prime.at n=22A052430
- n written efficiently in natural numbers base, i.e., in form ...wxyz where n = 1*z + 2*y + 3*x + 4*w + ... with z <= 1, y < 2, x < 3, w < 4, ...at n=22A055611
- Numbers k>11 such that x^k + x^11 + x^10 + x^9 + x^8 + x^7 + x^6 + x^5 + x^4 + x^3 + x^2 + x + 1 is irreducible over GF(2).at n=38A057488
- Multiples of 7 whose sum of digits is equal to 7.at n=27A063416
- Array in which the n-th row contains the multiples of n using nonzero digits and having a digit sum of n. Sequence contains the rows and a zero entry for rows with no terms (e.g. 10).at n=27A077755
- a(n) = 9*n^2 + 3*n + 1.at n=38A082040
- Factorial expansions of the entries in A085216.at n=19A085218
- Near-repunit semiprimes.at n=29A105993
- Triangle, read by rows, such that T(n,k) = T(n-1,k-1) + [T^2](n-2,k-1) with T(n,0) = T(n,n) = 1 for n>=0, k>=0.at n=58A113983
- Column 3 of triangle A113983; also a(n) = A113983(n+2,2) + [A113983^2](n+1,2).at n=7A113986
- a(n) = 3*a(n-1) + 4*a(n-2), with a(0) = 3, a(1) = 7, a(3) = 9, for n > 2.at n=7A115164
- Zero-free numbers with digit sum equal to 7.at n=51A119461
- Floor of the area of consecutive Prime-Indexed Prime triangles.at n=8A119659
- Describe prime factorization of n (primes in ascending order and with repetition) (method A - initial term is 2).at n=31A123132
- Numbers k such that k, k + 1 and k + 2 are 3 consecutive Harshad numbers.at n=35A154701