8291
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 8292
- 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
- 8290
- Möbius Function
- -1
- Radical
- 8291
- 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
- 39
- 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
- yes
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 1040
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Smallest prime p==3 (mod 8) such that Q(sqrt(-p)) has class number 2n+1.at n=23A002148
- Primes of form 3*k^2 - 3*k + 23.at n=41A007637
- 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 91.at n=2A031589
- Numbers k such that 191*2^k+1 is prime.at n=19A032472
- Primes that are decimal concatenations of n with n + 9.at n=14A032632
- Multiplicity of highest weight (or singular) vectors associated with character chi_170 of Monster module.at n=39A034558
- Let a (resp. b,c,d) be number of primes in the range {2..p} that end in 1 (resp. 3,7,9); sequence gives p such that a=d and b=c.at n=43A038562
- Largest prime substring in n! (0 if none).at n=14A046277
- Primes q of the form q = 10p + 1, where p is also prime.at n=34A055781
- A B_2 sequence: a(n) is the smallest prime such that the pairwise sums of distinct elements are all distinct.at n=43A062294
- Primes containing 2k digits in which the sum of the first k digits is that of the last k digits.at n=50A068896
- a(1) = 1, then the smallest prime divisor of A065447(n) not included earlier.at n=17A087552
- Denominator(Bernoulli(n-1) + 1/n)=66, where n runs through the primes.at n=38A090799
- Primes of the form 37n+3.at n=32A100203
- Smaller of twin primes of the form 6*p(j)*p(k)-1, 6*p(j)*p(k)+1 where p(i)=i-th prime.at n=43A102168
- Triangle T read by rows: matrix product of Pascal and Catalan triangle.at n=38A104259
- Minimal set of prime-strings in base 10 for primes of the form 4n+3 in the sense of A071062.at n=23A111056
- Primes p such that there exist three primes q, r and s with p^3=q^3+r^3+s^3.at n=13A114923
- Seventh column of triangle A115193 (called C(1,2)).at n=4A115204
- Prime semiperimeters of quadrilaterals with sides which are four consecutive primes.at n=39A131021