8423
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
- 8424
- 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
- 8422
- Möbius Function
- -1
- Radical
- 8423
- 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
- no
- Safe Prime
- yes
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 1053
- 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 68.at n=26A020407
- Primes that remain prime through 3 iterations of function f(x) = 10x + 9.at n=27A023301
- 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=11A031589
- Number of partitions of n with equal nonzero number of parts congruent to each of 1 and 2 (mod 5).at n=46A035566
- Primes of the form n*phi(n)-1 where phi is the Euler function (in order of appearance).at n=43A046078
- Numbers k such that 2^k + 3^k is a semiprime.at n=29A050244
- Primes that are congruent to -1 mod n, where n is the index of the prime.at n=9A052013
- Prime numbers k such that (2^k + 3^k)/5 is prime.at n=9A057469
- Numbers k such that k*2^m+1 are composites for all exponents m in the range 0<=m<=k.at n=21A061153
- Potential Sierpiński numbers: integers for which the smallest m > 2^10 in A040076 such that n*2^m+1 is prime (A050921).at n=33A064721
- Primes of the form sum 6d/(2 + mu(d)) for some k and all d dividing k.at n=22A069548
- Safe primes (A005385) (p and (p-1)/2 are primes) such that 6*p+1 is also prime.at n=33A075705
- a(n) is the least positive integer k such that g(k) = n*g(k-1), where g(k) = prime(k+1) - prime(k).at n=23A078563
- Numbers n such that when the digits of Fibonacci(n) are sorted into decreasing order and zeros are dropped it is a prime.at n=48A082922
- Primes which are also prime if their base 32 representation is interpreted as a base 10 number.at n=43A090716
- Number of A095285-primes in range ]2^n,2^(n+1)].at n=16A095295
- Number of A095323-primes in range ]2^n,2^(n+1)].at n=16A095325
- a(n) = A000040(A096480(n)).at n=23A096481
- Primes from merging of 4 successive digits in decimal expansion of the Euler-Mascheroni constant A001620.at n=35A104938
- Smallest prime p > 3 such that p-1 has a prime factor > (p-1)^(n/(n+1)).at n=11A111671