16841
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
- 18384
- Proper Divisor Sum (Aliquot Sum)
- 1543
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 15300
- Möbius Function
- 1
- Radical
- 16841
- 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
- 66
- 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
- Number of paraffins.at n=40A005998
- Pseudoprimes to base 15.at n=27A020143
- Number of partitions in parts not of the form 19k, 19k+3 or 19k-3. Also number of partitions with at most 2 parts of size 1 and differences between parts at distance 8 are greater than 1.at n=40A035972
- a(n) = (-1)^(n+1)/3/(2n+1) * Sum_{k=0..n} 16^k*B(2k)*C(2n+1,2k) where B(k) denotes the k-th Bernoulli number.at n=4A076552
- Number of irreducible polynomials (over the rationals) of form a*x^2+b*x+c, 1 <= a,b,c <= n.at n=25A079671
- a(n) = 15*n*(n+1) + 11.at n=33A132208
- A141479(n+1)/3.at n=9A147719
- Numbers n with property that n^2 is a concatenation of three 3-digit primes.at n=22A153139
- Base-11 Armstrong or narcissistic numbers (written in base 10).at n=19A161948
- Nonprime numbers with all divisors starting and ending with digit 1.at n=32A208261
- Number of isomorphism classes of reduced Witt rings of fields with 2n orderings.at n=21A213331
- Number of isomorphism classes of reduced Witt rings of fields with n orderings.at n=43A213332
- Number of isomorphism classes of reduced Witt rings of fields with n orderings.at n=44A213332
- Inverse Moebius transform of Catalan numbers.at n=9A237670
- Number of n X 3 nonnegative integer arrays with upper left 0 and lower right its king-move distance away minus 2 and every value within 2 of its king move distance from the upper left and every value increasing by 0 or 1 with every step right, diagonally se or down.at n=23A253218
- Composite numbers k with its divisors having the property that the last digit of every divisor is the same as the first digit of the next divisor.at n=35A307858
- Sum of the squarefree parts of the partitions of n into 8 parts.at n=31A309484
- Square array T(n,k), n >= 1, k >= 1, read by antidiagonals downwards, where T(n,k) = Sum_{j=1..n} floor(n/(2*j-1))^k.at n=61A350122