8971
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 25
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 8972
- 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
- 8970
- Möbius Function
- -1
- Radical
- 8971
- 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
- 140
- 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
- 1116
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Let q_k = p*(p+2) be product of k-th pair of twin primes; sequence gives values of p+2 such that (q_k)^2 > q_{k-i}*q_{k+i} for all 1 <= i <= k-1.at n=45A021007
- a(n) = a(n-1) + a(n-2) + 1 for n>1, a(0)=0, a(1)=4.at n=17A022309
- a(n) = Sum_{k=0..n} (k+1) * A026725(n, k).at n=10A027211
- 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 93.at n=28A031591
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 62 ones.at n=10A031830
- Numbers whose set of base-13 digits is {1,4}.at n=22A032825
- Expansion of (1/(1-x^2))*Product_{m>=0} 1/(1-x^(2m+1)).at n=45A038348
- Discriminants of imaginary quadratic fields with class number 19 (negated).at n=23A046016
- Number of positive terms in a symmetric determinant of order n.at n=8A059423
- Primes p such that p^10 reversed is also prime.at n=35A059703
- a(1) = 1 and then the smallest primes such that all a(k)-a(j) are distinct composite numbers.at n=42A079850
- Primes p such that (r-p)/log(p) > 3, where r is the next prime after p.at n=24A082888
- Numbers n such that A003313(n) = A003313(2n).at n=38A086878
- prime(k) for those k where floor((2*(prime(k+1)-prime(k))*PrimePi(k) mod (8*k))/k) = m with m = 9.at n=8A109563
- One seventh of the sum of the first n primes, when an integer.at n=22A112272
- Primes of the form f(n) = 9*n^4 - 444*n^3 + 8059*n^2 - 63714*n + 185371 listed by increasing value of n >= 0.at n=6A117225
- Primes of the form prime(n+1)*prime(n+3) - prime(n)*prime(n+2) - 1, ordered by n.at n=31A118624
- Primes p such that q-p = 28, where q is the next prime after p.at n=4A124595
- a(n) is the number of integer lattice points inside the right triangle with legs 3n and 4n (and hypotenuse 5n).at n=38A126587
- Toothpick primes: primes in the toothpick sequence A139250.at n=38A139253