16261
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- yes
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 19584
- Proper Divisor Sum (Aliquot Sum)
- 3323
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 13200
- Möbius Function
- -1
- Radical
- 16261
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 3
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
- no
- 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
- Palindromes of form k^2 + k + 5.at n=7A027728
- "CGK" (necklace, element, unlabeled) transform of 1,2,3,4,...at n=15A032158
- Palindromic and divisible by 7.at n=41A045642
- Composite palindromes whose sum of prime factors is palindromic (counted with multiplicity).at n=26A046354
- Composite palindromes whose sum of prime factors is prime (counted with multiplicity).at n=38A046365
- Trajectory of 23 under map that sends x to 3x - sigma(x), where sigma(x) is the sum of the divisors of x.at n=12A058545
- Numbers n such that n and 2n+1 are both palindromes.at n=35A069881
- Numbers n for which there are exactly seven k such that n = k + reverse(k).at n=29A072431
- Palindromic odd composite numbers that are the products of an odd number of distinct primes.at n=34A075808
- Smallest palindrome beginning with n and digit sum n, or 0 if no such number exists.at n=15A082217
- Smallest palindrome beginning with n and a digit sum of n at some stage.at n=15A082935
- Palindromes k such that 3k + 1 is also a palindrome.at n=20A083829
- Numbers n such that the numerator of Sum_{i=1..n} (1/i^2), in reduced form, is prime.at n=31A111354
- a(n+1) = least palindrome not already used that is either a divisor or multiple of a(n) such that the ratios a(n+1)/a(n) are all distinct.at n=13A111678
- Palindromic composites such that some digit permutation is prime.at n=40A119378
- Palindromic numbers that contain the sum of their digits as a substring.at n=19A121939
- Number of subtrees of a complete binary tree.at n=24A157679
- Alternating partial sums of the Floor-Sqrt transform of central binomial coefficients.at n=16A192659
- Number of (w,x,y,z) with all terms in {0,...,n} and w=max{w,x,y,z}-min{w,x,y,z}; i.e., the range of (w,x,y,z) is its first term.at n=20A212744
- E.g.f.: Sum_{n>=0} D^(n*(n-1)/2) (x + x^2)^(n*(n+1)/2) / (n*(n+1)/2)!, where operator D^n = d^n/dx^n.at n=6A215126