16869
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 30
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 22496
- Proper Divisor Sum (Aliquot Sum)
- 5627
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 11244
- Möbius Function
- 1
- Radical
- 16869
- 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
- 58
- 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 continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 86.at n=36A031584
- Number of partitions of n into parts not of the form 19k, 19k+2 or 19k-2. Also number of partitions with 1 part of size 1 and differences between parts at distance 8 are greater than 1.at n=42A035971
- a(n) = a(1) + a(2) + ... + a(n-1) - a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1, a(2) = 3, and a(3) = 4.at n=15A049928
- Smallest composite that when added to sum of prime factors reaches a prime after n iterations.at n=42A050710
- Least k for the Theodorus spiral to complete n revolutions.at n=40A072895
- First element of first run of exactly n consecutive numbers not of form x^2+y^2.at n=19A104271
- A recursion triangle sequence: A(n,k) = A(n-1,k-1)+e(n-1,k) where e(n,k)=Sum[(-1)^j Binomial[n + 1, j](k - j)^n, {j, 0, k}].at n=49A157744
- a(n) = (a(n-1) * a(n-3) - (-1)^n * a(n-2)^2) / a(n-4) with a(0) = 1, a(1) = 1, a(2) = 0, a(3) = 1, a(6) = 2.at n=21A247370
- Smallest term of the first run of at least n consecutive integers which are not sums of 2 squares.at n=19A260157
- Number of length n inversion sequences avoiding the patterns 010, 120, and 210.at n=9A279558
- a(n) = (8*n^3 + 12*n^2 + 4*n - 9)/3.at n=17A358035