8243
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 8244
- Proper Divisor Sum (Aliquot Sum)
- 1
- 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
- 8242
- Möbius Function
- -1
- Radical
- 8243
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
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
- 65
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- yes
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 1035
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Numbers k such that the continued fraction for sqrt(k) has period 82.at n=17A020421
- Primes that remain prime through 3 iterations of function f(x) = 2x + 7.at n=9A023275
- Primes that remain prime through 3 iterations of function f(x) = 3x + 4.at n=8A023278
- a(n+1) = [ A*a(n)+B ]/p^r, where p^r is the highest power of p diving [ A*a(n)+B ] and p=2, A=2.00013, B=3.0.at n=38A029580
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 89.at n=32A031587
- Lower prime of a difference of 20 between consecutive primes.at n=10A031938
- Decimal part of cube root of a(n) starts with 2: first term of runs.at n=19A034128
- Numbers whose base-4 representation contains exactly four 0's and no 1's.at n=31A045033
- Numbers whose base-4 representation contains exactly four 0's and two 3's.at n=21A045083
- Primes with first digit 8.at n=44A045714
- Discriminants of imaginary quadratic fields with class number 21 (negated).at n=24A046018
- Integers n such that A047988(n)=3.at n=39A047986
- Fourth term of weak prime quintets: p(m-2)-p(m-3) < p(m-1)-p(m-2) < p(m)-p(m-1) < p(m+1)-p(m).at n=21A054826
- Primes that can be formed by concatenating 2^a and 3^b.at n=27A068801
- Initial terms of groups in A075639.at n=45A075641
- First row of square array A082011.at n=45A082012
- Primes in which odd positioned digits are prime and even positioned digits are composite. The least significant digit is taken to be the first digit.at n=45A083820
- a(1) = 1; for n>1, a(n) = smallest prime > a(n-1) such that a(1)*...*a(n) + 2 is a prime.at n=44A085013
- Primes that represent some mean of 4 consecutive (2 smaller, itself, 1 larger) primes.at n=21A094932
- Primes of the form a^5 + b^3 with a,b>0.at n=16A100273