1871
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 1872
- 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
- 1870
- Möbius Function
- -1
- Radical
- 1871
- 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
- 130
- 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
- 286
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- a(n) is the solution to the postage stamp problem with n denominations and 5 stamps.at n=11A001215
- Smallest prime p such that the product of q/(q-1) over the primes from prime(n) to p is greater than 2.at n=12A001275
- Artiads: the primes p == 1 (mod 5) for which Fibonacci((p-1)/5) is divisible by p.at n=12A001583
- Quintan primes: p = (x^5 + y^5)/(x + y).at n=8A002650
- a(n) = n^3 + n^2 - 1.at n=11A003777
- Prime triples: p; p+2 or p+4; p+6 all prime.at n=46A007529
- Prime quadruples: numbers k such that k, k+2, k+6, k+8 are all prime.at n=6A007530
- Coordination sequence T1 for Zeolite Code ATT.at n=31A008041
- Coordination sequence T9 for Zeolite Code EUO.at n=27A008104
- Coordination sequence T2 for Zeolite Code LTL.at n=32A008139
- Harmonic Molien series for Conway group Con.0.at n=36A008924
- If a, b in sequence, so is ab+5.at n=27A009304
- a(n) = floor( Gamma(n+1/2) ).at n=7A014510
- Nearest integer to Gamma(n+1/2).at n=7A014521
- Numbers k such that phi(k + 13) | sigma(k).at n=50A015833
- Expansion of 1/(1-x^10-x^11-x^12-x^13-x^14-x^15).at n=69A017891
- Numbers k such that the continued fraction for sqrt(k) has period 48.at n=10A020387
- Let q_k=p(p+2) be product of k-th pair of twin primes; sequence gives values of p such that (q_k)^2 > q_{k-i}q_{k+i} for all 1 <= i <= k-1.at n=21A021005
- Initial members of prime triples (p, p+2, p+6).at n=22A022004
- Numbers k such that k and 8*k + 1 are both prime.at n=50A023228