8539
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
- 8540
- 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
- 8538
- Möbius Function
- -1
- Radical
- 8539
- 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
- 127
- 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
- 1065
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Sum{T(i,j)}, 0<=i<=n, 0<=j<=n, T given by A026692.at n=11A026701
- 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=22A031589
- Primes p such that both p-2 and 2p-1 are prime.at n=44A038869
- Discriminants of imaginary quadratic fields with class number 17 (negated).at n=20A046014
- Digitally balanced numbers in both bases 2 and 3.at n=11A049361
- Primes p such that p^12 reversed is also prime.at n=19A059705
- Integers n > 1997 such that the 'Reverse and Add!' trajectory of n joins the trajectory of 1997.at n=10A063055
- a(n) = floor((n+2)^(n+2)/n^n).at n=33A078111
- Primes p such that the sum of the digits of p is not prime, but the sum of the squares of the digits of p is prime.at n=12A091362
- Prime numbers p such that primepi(p) + p is a square.at n=11A104269
- Beginning with 3, least prime such that concatenation of first n terms and its digit reversal both are primes.at n=20A113584
- Nearest integer to locations of increasingly large peaks of abs(zeta(0.5 + i*2*(Pi/log(2))*t)) for increasing real t.at n=46A117536
- Locations of the increasing peak values of the integral of the absolute value of the Riemann zeta function between successive zeros on the critical line. This can also be defined in terms of the Z function; if t and s are successive zeros of a renormalized Z function, z(x) = Z(2 Pi x/log(2)), then take the integral between t and s of |z(x)|. For each successively higher value of this integral, the corresponding term of the integer sequence is r = (t+s)/2 rounded to the nearest integer.at n=22A117538
- Prime sums of 7 positive 5th powers.at n=42A123036
- Primes in A023108(n); or Lychrel primes.at n=19A135316
- Primes of the form 4x^2+4xy+331y^2.at n=32A140000
- Primes of the form 3x^2+616y^2.at n=34A140029
- Primes of the form 19x^2+14xy+91y^2.at n=33A140624
- Primes congruent to 13 mod 29.at n=39A141989
- Primes congruent to 14 mod 31.at n=34A142018