8185
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 22
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 9828
- Proper Divisor Sum (Aliquot Sum)
- 1643
- 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
- 6544
- Möbius Function
- 1
- Radical
- 8185
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 127
- Smith Number
- yes
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- Squarefree Number
- yes
- Prime Power
- no
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- a(n) = ceiling(n*phi^15), where phi is the golden ratio, A001622.at n=6A004970
- Molien series for 6-dimensional complex reflection group 4.U_4 (3) of order 2^9 .3^7 .5.7.at n=50A008581
- Number of partitions of n that do not contain 8 as a part.at n=33A027342
- Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted then there are a pair of central terms both equal to 8.at n=13A031421
- Number of partitions of n such that cn(0,5) = cn(1,5) < cn(2,5) = cn(4,5) < cn(3,5).at n=71A036874
- Number of partitions satisfying cn(0,5) + cn(1,5) <= cn(2,5) and cn(0,5) + cn(1,5) <= cn(3,5) and cn(0,5) + cn(4,5) <= cn(2,5) and cn(0,5) + cn(4,5) <= cn(3,5).at n=44A039882
- a(n) = T(7,n), array T given by A048483.at n=10A048490
- Numbers k such that k | sigma_11(k) - phi(k)^11.at n=11A055705
- Local ranks of terms of A057122.at n=43A057124
- a(n) is the greatest integer m such that (1) written in base n it is also readable as if it is in factorial base and (2) this factorial base value is smaller than or equal to m.at n=2A065399
- Interprimes which are of the form s*prime, s=5.at n=20A075280
- a(n) = 4*n^2 + 10*n + 1.at n=44A082112
- a(n) = 3*a(n-1) - a(n-2) - 3*a(n-3) + 2*a(n-4).at n=13A084174
- Define d(n,k) to be the number of '1' digits required to write out all the integers from 1 through k in base n. E.g., d(10,9) = 1 (just '1'), d(10,10) = 2 ('1' and '10'), d(10,11) = 4 ('1', '10' and '11'). Then a(n) is the first k >= 1 such that d(n,k) > k.at n=7A092175
- 2^p - 7 where p is prime.at n=5A098815
- Triangle read by rows: even-numbered rows of A106580.at n=60A106585
- Numbers n such that n^2-6 and n^2+6 are both prime.at n=35A108403
- A 9th-order Fibonacci sequence.at n=19A127193
- Numbers k such that k divides Sum_{j=1..k} prime(j)^15.at n=6A131275
- a(n) = prime(n^2) - n^2.at n=33A141129