1867
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
- 4
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 1868
- 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
- 1866
- Möbius Function
- -1
- Radical
- 1867
- 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
- 37
- 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
- 285
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- A self-generating sequence: a(1)=1, a(2)=2, a(n+1) chosen so that a(n+1)-a(n-1) is the first number not obtainable as a(j)-a(i) for 1<=i<j<=n.at n=48A001149
- Class 4+ primes (for definition see A005105).at n=31A005108
- Class 4- primes (for definition see A005109).at n=42A005112
- Primes p such that 2p-1 is also prime.at n=49A005382
- Number of unrooted triangulations of a hexagon with n internal nodes.at n=4A005502
- Odd numbers not of form p + 2^k (de Polignac numbers).at n=42A006285
- Numbers k such that k-6, k, and k+6 are primes.at n=46A006489
- Where the prime race among 5k+1, ..., 5k+4 changes leader.at n=16A007353
- Prime triples: p; p+2 or p+4; p+6 all prime.at n=45A007529
- Coordination sequence T4 for Zeolite Code LTN.at n=30A008143
- Smallest positive number that can be written as sum of distinct Fibonacci numbers in n ways.at n=41A013583
- From table of maximal epacts e(p) and corresponding primes p, for x_0=2, x_{m+1} = (x_m)^2-1; sequence gives p.at n=22A014426
- Primes p==1 (mod 6) such that 3 and -3 are both cubes (one implies other) modulo p.at n=44A014753
- Numbers k such that the continued fraction for sqrt(k) has period 30.at n=20A020369
- Smallest nonempty set S containing prime divisors of 8k+3 for each k in S.at n=47A020617
- Initial members of prime triples (p, p+4, p+6).at n=23A022005
- Initial members of prime 5-tuples (p, p+4, p+6, p+10, p+12).at n=2A022007
- Primes that remain prime through 2 iterations of function f(x) = x + 6.at n=47A023241
- Primes that remain prime through 2 iterations of function f(x) = 4x + 9.at n=38A023251
- Primes that remain prime through 2 iterations of function f(x) = 5x + 2.at n=27A023252