13681
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 13682
- 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
- 13680
- Möbius Function
- -1
- Radical
- 13681
- 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
- 58
- 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
- 1616
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Primes of the form k^2 - 8.at n=25A028886
- 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 15.at n=7A031603
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 60 ones.at n=37A031828
- Concatenation of prime p and nextprime(p) is prime -> cycles of 2 steps possible.at n=2A036339
- Primes p such that (p+1)/2 and (p+2)/3 are also primes.at n=32A036570
- Primes resulting from procedure described in A048388.at n=27A048389
- First member of a prime quadruple in a 2p-1 progression.at n=8A057327
- Primes with 22 as smallest positive primitive root.at n=3A061334
- 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=[6, 4,2]; short d-string notation of pattern = [642].at n=20A078855
- Primes p such that the differences between the 5 consecutive primes starting with p are (6,4,2,4).at n=8A078961
- a(n) = 15*n^2 + 6*n + 1.at n=30A080861
- Beginning with 2, least prime not occurring earlier such that the concatenation of first n terms has the least prime factor prime(n).at n=39A100759
- Primes connected to two primes by the (p+1)/2 and 2p-1 operators.at n=33A109835
- Numbers k such that Fibonacci(prime(k)) is prime.at n=34A119984
- Numbers n such that Lucas(prime(n)) is prime, where Lucas = A000032.at n=43A120561
- Primes p such that Lucas(prime(p)) is prime, where Lucas = A000032.at n=9A123677
- Centered triangular numbers that are prime.at n=21A125602
- Mountain primes.at n=38A134951
- Prime numbers p such that p +- ((p-1)/2) are primes.at n=31A137702
- Prime numbers p such that p +- ((p-1)/8) are primes.at n=11A137771