16509
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 22016
- Proper Divisor Sum (Aliquot Sum)
- 5507
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 11004
- Möbius Function
- 1
- Radical
- 16509
- 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
- 172
- 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
- Partial sums of A001037, omitting A001037(1).at n=16A001036
- s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = (composite numbers), t = (F(2), F(3), ...).at n=14A024589
- Write 0, 1, ..., n in base 3 and add as if they were decimal numbers.at n=39A121718
- Number of base 25 n-digit numbers with adjacent digits differing by one or less.at n=7A126379
- 1/8 the number of n X n arrays of squares of integers with every 2X2 subblock summing to 17.at n=12A159217
- Sums of three Mersenne primes.at n=33A174055
- a(n) = Sum_{d|n} phi(d^tau(d)).at n=13A179115
- Number of n X 7 binary arrays without the pattern 0 1 diagonally, vertically or antidiagonally.at n=23A188864
- Number of non-abelian groups of order prime(n)^6.at n=18A271811