8517
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 12096
- Proper Divisor Sum (Aliquot Sum)
- 3579
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 5312
- Möbius Function
- -1
- Radical
- 8517
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 127
- 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
- Expansion of log(1+log(1+x))*exp(x).at n=7A009315
- Expansion of 1/(1-x)^2/(1-x^2)/(1-x^3)/(1-x^5)/(1-x^8).at n=38A034379
- Numbers k such that k^4 can be written as a sum of four positive 4th powers with no common factor.at n=26A039664
- Numbers k such that phi((prime(k)-1)/2) = sigma(k).at n=31A068474
- a(1) = 9, then the smallest number such that the forward as well as the reverse n-th partial concatenation is a prime for n>1. (Reverse concatenation is taken term-wise and not digit-wise).at n=17A083995
- Multiples of 17 containing a 17 in their decimal representation.at n=17A121037
- Odd interprimes divisible by 17.at n=28A124620
- Number of 2 X 2 singular integer matrices with entries from {2,...,n}.at n=45A134978
- 3 times heptagonal numbers: a(n) = 3*n*(5*n-3)/2.at n=34A152773
- Multiples of 17 whose reversal - 1 is also a multiple of 17.at n=31A166398
- Number of nondecreasing arrangements of 6 numbers x(i) in -(n+4)..(n+4) with the sum of sign(x(i))*2^|x(i)| zero.at n=26A187990
- Binomial sum related to rooted trees.at n=8A188289
- A007185(n)/5^n.at n=14A214882
- Numbers k such that sigma(tau(phi(k))) = phi(tau(sigma(k))).at n=36A226118
- a(0) = 1; for n>0, a(n) is the smallest positive integer that has not previously occurred such that a(n-1)^2 + n^2 + a(n) is a square.at n=16A347595
- Numbers k that set a new record m where m is the largest left-truncatable prime up to the final k (stop on reaching the final k).at n=5A355458
- a(1) = 1; for n > 1, a(n) is the smallest unused positive number such that sopfr(|a(n) - a(n-1)|) = sopfr(a(n) + a(n-1)) and Omega(|a(n) - a(n-1)|) = Omega(a(n) + a(n-1)), where sopfr(k) is the sum of the primes dividing k, with repetition.at n=5A370503
- Square roots of partial sums of A386369 that are square numbers.at n=11A386370