12539
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 12540
- Proper Divisor Sum (Aliquot Sum)
- 1
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 12538
- Möbius Function
- -1
- Radical
- 12539
- 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
- 138
- 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
- yes
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 1497
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Primes that remain prime through 3 iterations of function f(x) = 3x + 2.at n=12A023277
- Primes that remain prime through 3 iterations of function f(x) = 9x + 8.at n=32A023298
- Primes that remain prime through 4 iterations of function f(x) = 3x + 2.at n=3A023307
- Convolution of odd numbers and A001950.at n=23A023659
- Expansion of (2 + x + x^2)/((1 - x)*(1 - x - x^2)).at n=16A026390
- Primes of form k^2 - 5.at n=24A028877
- Multiplicity of highest weight (or singular) vectors associated with character chi_76 of Monster module.at n=37A034464
- Primes which are not the sum of consecutive composite numbers.at n=36A037174
- Numbers k such that 281*2^k + 1 is prime.at n=20A053357
- Trajectory of n under the Reverse and Add! operation carried out in base 4 (presumably) does not reach a palindrome and (presumably) does not join the trajectory of any term m < n.at n=37A075421
- Primes p such that the number of distinct prime divisors of all composite numbers between p and the next prime is 5.at n=21A075585
- Safe primes (A005385) (p and (p-1)/2 are primes) such that 8*p+1 (A023228) is also prime.at n=33A075706
- Number of times the n-th prime appears among the decimal digits of 2^(2^n) + 1, the Fermat numbers.at n=21A078671
- Initial term in sequence of four consecutive primes separated by 3 consecutive differences each <=6 (i.e., when d=2,4 or 6) and forming d-pattern=[2, 6,6]; short d-string notation of pattern = [266].at n=7A078849
- Smallest balanced prime of order n.at n=39A082080
- a(n) = r-th prime of the form (p-q)/(q-r) with r=prime(n+1), q=prime(n+2), and primes p > q.at n=47A089577
- a(n) = smallest k such that the base 4 Reverse and Add! trajectory of A075421(n) joins the trajectory of k.at n=37A091676
- Primes of the form p*q + p + q, where p and q are two successive primes.at n=16A096342
- Primes A005382(n) + A005384(n) - 1 with a twin prime A005382(n) + A005384(n) + 1.at n=20A099109
- a(n) = prime(n)*prime(n+1) + prime(n) + prime(n+1).at n=28A126199