15968
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 29
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 31500
- Proper Divisor Sum (Aliquot Sum)
- 15532
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7968
- Möbius Function
- 0
- Radical
- 998
- Omega Function (Ω)
- 6
- 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
- 53
- 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
- Sum of first prime(n) primes.at n=22A022094
- Numbers k such that k divides the (left) concatenation of all numbers <= k written in base 13 (most significant digit on right and removing all least significant zeros before concatenation).at n=13A029530
- 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 63.at n=26A031561
- Breadth-first-wise A014486-like encoding of A080299-trees.at n=8A080313
- Triangle read by rows: T(n,k) is the number of Motzkin paths of length n and having k peaks at odd height.at n=50A097891
- Sum of the first 2n+1 primes.at n=41A109723
- a(n) = a(n-1) + 2*a(n-2) - a(n-3) - a(n-4), a(0)=0, a(1)=8, a(2)=10, a(3)=18.at n=17A153382
- Second bisection of A153382.at n=8A153388
- E.g.f. satisfies: A(x) = (exp(x*A(x)) + exp(x/A(x)))/2.at n=7A195510
- Sequence of coefficients of x in marked mesh pattern generating function Q_{n,132}^(0,0,4,0)(x).at n=6A212341
- Numbers of the form 5^j + 7^k, for j and k >= 0.at n=33A226818
- Somos's sequence {a(7,n)} defined in comment in A018896: a(0)=a(1)= ... = a(15) = 1; for n>=16, a(n) = (a(n-1)*a(n-15)+ a(n-8)^2)/a(n-16).at n=38A271837
- Number of integer partitions of n whose run-lengths are not unimodal.at n=41A332281
- The sum S of the maximum number of consecutive primes starting with 2 such that S <= prime(n)^2.at n=30A346134
- a(n) = 1 + Sum_{k=0..n-1} binomial(n+2,k+3) * a(k).at n=7A352861
- Numbers k such that x=(sigma(k) XOR 2*k) divides k in carryless binary arithmetic, when the binary expansions of k and x are interpreted as polynomials in ring GF(2)[X].at n=44A379236
- a(n) = (1/2) * Sum_{k=0..floor(n/3)} 2^(n-2*k) * binomial(2*n-4*k+2,2*k+1).at n=8A387602