8689
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 31
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 8690
- 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
- 8688
- Möbius Function
- -1
- Radical
- 8689
- 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
- 47
- 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
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 1082
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Eight iterations of Reverse and Add are needed to reach a palindrome.at n=27A015988
- Numbers k such that the continued fraction for sqrt(k) has period 25.at n=28A020364
- s(n+3)/2, where s is A024945.at n=15A024946
- Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 12.at n=6A031600
- Primes that are concatenations of n with n + 3.at n=10A032626
- Triangle of D-analogs of Stirling numbers of the 2nd kind.at n=46A039760
- Triangle of D-analogs of Stirling numbers of the 2nd kind.at n=53A039761
- a(n) = Sum_{i=0..2n} (-1)^i * T(i,2n-i), array T as in A049735.at n=26A049737
- Primes whose digits are composite; primes having only {4, 6, 8, 9} as digits.at n=14A051416
- Primes having only {0, 6, 8, 9} as digits.at n=11A053580
- a(n) = T(n,n-5), array T as in A055801.at n=31A055805
- Primes with 13 as smallest positive primitive root.at n=20A061326
- Primes having only 0,4,6,8,9 as digits.at n=25A061372
- Numbers which need eight 'Reverse and Add' steps to reach a palindrome.at n=22A065213
- a(n) = prime(n*(n+1)/2 + 1).at n=46A078721
- Prime numbers using only the curved digits 0, 3, 6, 8 and 9.at n=40A079652
- Diagonal of triangular spiral in A051682.at n=43A081270
- Primes p such that p*(p-2) divides 3^(p-1)-1.at n=6A081764
- Primes which are also prime if their base 31 representation is interpreted as a base 10 number.at n=43A090715
- Fundamental discriminants of real quadratic number fields with class number 5.at n=41A094614