16551
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 24560
- Proper Divisor Sum (Aliquot Sum)
- 8009
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 11016
- Möbius Function
- 0
- Radical
- 1839
- Omega Function (Ω)
- 4
- 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
- 120
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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
- a(n) = Sum_{k = 1..n} floor(2^k / k).at n=16A000801
- Discriminants of totally complex sextic fields (negated).at n=8A023687
- Denominators of continued fraction convergents to sqrt(433).at n=10A041825
- Number of binary strings of length n with no substrings equal to 0001 0010 or 0101.at n=14A164446
- Numbers k such that k^2+1 = 2p,(k+1)^2+1 = 5q, (k+2)^2+1 = 10r where p, q, and r are primes.at n=22A181619
- Monotonic ordering of nonnegative differences 7^i-2^j, for 40>=i>=0, j>=0.at n=37A192119
- Monotonic ordering of nonnegative differences 7^i-4^j, for 40>=i>=0, j>=0.at n=20A192166
- Numbers k such that k and k+1 are both of the form p*q^3 where p and q are distinct primes.at n=16A215173
- Denominators of convergents to 2*Pi.at n=6A242859
- Numbers k such that (68*10^k + 7)/3 is prime.at n=28A270613
- Numbers k such that 8*10^k - 51 is prime.at n=20A290330
- Number of n X n 0..1 arrays with every element equal to 1, 3, 4, 5 or 8 king-move adjacent elements, with upper left element zero.at n=5A298828
- Number of nX6 0..1 arrays with every element equal to 1, 3, 4, 5 or 8 king-move adjacent elements, with upper left element zero.at n=5A298832
- T(n,k)=Number of nXk 0..1 arrays with every element equal to 1, 3, 4, 5 or 8 king-move adjacent elements, with upper left element zero.at n=60A298834
- G.f.: Sum_{n>=0} (n+1)*(n+2)/2 * x^n * (1 + x^n)^n.at n=40A326003
- Odd numbers k such that A173557(k) = A173557(sigma(k)), where A173557(n) is multiplicative with a(p^e) = p-1 and sigma is the sum of divisors function.at n=19A387159