15871
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 22
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 16200
- Proper Divisor Sum (Aliquot Sum)
- 329
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 15544
- Möbius Function
- 1
- Radical
- 15871
- 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
- 128
- 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 k such that the period of the continued fraction for sqrt(k) contains exactly 43 ones.at n=0A031811
- Number of ways to partition n labeled elements into sets of different sizes of at least 2 and order the sets.at n=10A032013
- a(n) = floor( sqrt(2) * (3/2)^n ).at n=23A033320
- Numerators of continued fraction convergents to sqrt(465).at n=9A041886
- A sequence of asymptotic density zeta(10) - 1, where zeta is the Riemann zeta function.at n=15A143036
- a(n) = 512n - 1.at n=30A158011
- a(n) = 529*n + 1.at n=29A158368
- a(n) = 30*n^2 + 1.at n=23A158558
- a(n) = 62*n^2 - 1.at n=15A158680
- a(n) is the n-th J_19-prime (Josephus_19 prime).at n=8A163799
- a(n) = floor((1 + 1/Pi)^n).at n=34A179492
- G.f.: exp( Sum_{n>=1} (2*sigma(n^2) - sigma(n)^2) * x^n/n ).at n=18A195734
- The least number with exactly n ones in the continued fraction of its square root.at n=43A206578
- Number of compositions of n where the difference between largest and smallest parts equals 7 and adjacent parts are unequal.at n=15A214276
- Numbers n such that in Collatz (3x+1) trajectory of n, the number of terms < n equals number of terms > n.at n=35A217731
- Hilltop maps: number of nX7 binary arrays indicating the locations of corresponding elements not exceeded by any horizontal or antidiagonal neighbor in a random 0..3 nX7 array.at n=1A218809
- T(n,k)=Hilltop maps: number of nXk binary arrays indicating the locations of corresponding elements not exceeded by any horizontal or antidiagonal neighbor in a random 0..3 nXk array.at n=29A218810
- Hilltop maps: number of 2Xn binary arrays indicating the locations of corresponding elements not exceeded by any horizontal or antidiagonal neighbor in a random 0..3 2Xn array.at n=6A218811
- Number of composites removed in each step of the Sieve of Eratosthenes for 10^7.at n=21A227155
- Semiprimes generated by the polynomial 2 * n^2 + 29.at n=18A241554