17922
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
- 3
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 37440
- Proper Divisor Sum (Aliquot Sum)
- 19518
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 5712
- Möbius Function
- 1
- Radical
- 17922
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 4
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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 48
- 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
- yes
- Odd
- no
Appears in sequences
- Convolution of natural numbers n >= 1 with Fibonacci numbers F(k), for k >= -7, with F(-n)=(-1)^(n+1)*F(n).at n=25A037158
- Bessel function J_0(n) is a monotonically decreasing positive sequence.at n=34A046960
- a(n) = Sum_{d|n} d*Fibonacci(n/d).at n=21A066769
- Least n such that nextprime(p*n) > p*nextprime(n) where p runs through the prime numbers (if p is prime then nextprime(p)=p).at n=19A117102
- Expansion of 2*x*(6 + 5*x) / ((1 - x)*(1 - x - x^2)).at n=14A142245
- Triangle read by rows: T(n,k) is the number of dispersed Dyck paths of semilength n having k peak plateaux.at n=52A191399
- Numbers n such that n is both the average of some twin prime pair p, q (q = p+2) (i.e., n = p+1 = q-1) and is also the arithmetic mean of the four numbers consisting of the two primes before p and the two primes after q.at n=30A256620
- Expansion of phi(x)^2 / phi(-x^2) in powers of x where phi() is a Ramanujan theta function.at n=32A260314
- Numbers k such that (56*10^k + 223)/9 is prime.at n=21A275524
- Number of 5Xn 0..1 arrays with every element equal to 0, 2, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=11A303327
- Number of distinct sums i^3 + j^3 + k^3 + l^3 for 0<=i<=j<=k<=l<=n.at n=26A374711