16391
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
- 16872
- Proper Divisor Sum (Aliquot Sum)
- 481
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 15912
- Möbius Function
- 1
- Radical
- 16391
- 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
- 53
- 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 that are the sum of 8 positive 7th powers.at n=44A003375
- Expansion of (5 - 9*x + 6*x^2)/(1-x)^4.at n=36A080957
- a(1) = 11; a(n) = if n == 2 mod 3 then a(n-1)-3, if n == 0 mod 3 then a(n-1)-2, if n == 1 mod 3 then a(n-1)*2.at n=43A085688
- a(n) = 2^n + ceiling(n/2).at n=14A134522
- Members of A038512 of the form k, k+2, k+6, k+8.at n=20A155511
- a(n) = 4^n + n.at n=7A158879
- a(n) = smallest number that leads to a new fixed point under the base-2 Kaprekar map of A164884.at n=39A164887
- a(n) = 2^n + 7.at n=14A168415
- a(n) = 4^(n+1) + 7.at n=6A195463
- Minimal number (in decimal representation) with n nonprime substrings in base-4 representation (substrings with leading zeros are considered to be nonprime).at n=34A217104
- Numbers of the form 4^j + 7^k, for j and k >= 0.at n=35A226817
- Numbers of the form 7^x + y^7 with x, y >= 0.at n=21A250715
- a(n) = n*(25*n - 39)/2.at n=37A263231
- Number of multisets of nonempty words with a total of n letters over ternary alphabet containing the third letter such that within each prefix of a word every letter of the alphabet is at least as frequent as the subsequent alphabet letter.at n=8A293798
- Numbers k such that (32*10^k + 319)/9 is prime.at n=16A293856
- a(n) = A106315(A156552(n)).at n=45A324051
- a(n) = Sum_{k=1..n} (-1)^(n+k)*A087322(n,k).at n=10A341549
- Lexicographically first sequence of positive integers such that all terms are pairwise coprime and no subset sum is a power of 2.at n=19A363245