8147
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
- 8148
- 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
- 8146
- Möbius Function
- -1
- Radical
- 8147
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 96
- 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
- 1023
- 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=18A002148
- 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=21A031587
- a(n) = 2^n - 45 with n>5, a(5)=1.at n=8A036564
- Primes with first digit 8.at n=32A045714
- Triangle read by rows: T(n,k) = p(r), where r is the (n-k+1)-th number such that A001222(r+1) = k, and p(r) is the r-th prime.at n=54A050298
- a(n) = prime(2^n - 1).at n=9A051438
- Second term of strong prime 5-tuples: p(m)-p(m-1) > p(m+1)-p(m) > p(m+2)-p(m+1) > p(m+3)-p(m+2).at n=23A054809
- Primes p such that |p - q| is a square, where q is the reversal of p.at n=28A059798
- a(1) = 7; a(n) is smallest number > a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime.at n=43A074343
- Safe primes (A005385) (p and (p-1)/2 are primes) such that 6*p+1 is also prime.at n=32A075705
- Non-palindromic primes which on subtracting their reversal give perfect squares.at n=11A080177
- Non-palindromic primes which on subtracting their reversal gives perfect cubes.at n=11A080178
- Numbers k such that k! + k# - 1 is prime, where k# is the primorial function A034386(k).at n=22A081711
- First column of triangle A082737.at n=45A082739
- Integer quotients pi(m*prime(m))/m.at n=7A084298
- First column of triangle A093922.at n=45A093924
- Numbers m such that (15m-4, 15m-2, 15m+2, 15m+4) is a prime quadruple.at n=41A112540
- Primes such that the sum of the predecessor and successor primes is divisible by 23.at n=42A112847
- Primes p that remain prime through at least 2 iterations of the function f(p) = p^2 + 4.at n=21A116886
- Primes of the form prime(n+1)*prime(n+3) - prime(n)*prime(n+2) - 1, ordered by n.at n=37A118624