1873
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 1874
- 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
- 1872
- Möbius Function
- -1
- Radical
- 1873
- 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
- 86
- 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
- 287
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Narayana's cows sequence: a(0) = a(1) = a(2) = 1; thereafter a(n) = a(n-1) + a(n-3).at n=21A000930
- Sextan primes: p = (x^6 + y^6)/(x^2 + y^2).at n=9A002647
- Class 4+ primes (for definition see A005105).at n=32A005108
- Primes p such that (p+1)/2 is prime.at n=32A005383
- Prime self (or Colombian) numbers: primes not expressible as the sum of an integer and its digit sum.at n=31A006378
- From relations between Siegel theta series.at n=16A006476
- Numbers k such that k-6, k, and k+6 are primes.at n=47A006489
- Primorial -1 primes: primes p such that -1 + product of primes up to p is prime.at n=9A006794
- Primes with both 10 and -10 as primitive root.at n=54A007349
- Prime triples: p; p+2 or p+4; p+6 all prime.at n=47A007529
- Coordination sequence T2 for Zeolite Code LTN.at n=30A008141
- Coordination sequence T4 for Zeolite Code NON.at n=26A008215
- a(n) = floor(n*(n-1)*(n-2)/13).at n=30A011895
- a(n) = a(n-4) + a(n-5), with a(0)=1, a(1)=a(2)=a(3)=0, a(4)=1.at n=58A017827
- Numbers k such that the continued fraction for sqrt(k) has period 53.at n=1A020392
- Smallest nonempty set S containing prime divisors of 5k+8 for each k in S.at n=24A020600
- Let q_k = p*(p+2) be product of k-th pair of twin primes; sequence gives values of p+2 such that (q_k)^2 > q_{k-i}*q_{k+i} for all 1 <= i <= k-1.at n=21A021007
- Initial members of prime triples (p, p+4, p+6).at n=24A022005
- Number of 3's in n-th term of A022482.at n=30A022486
- Expansion of Product_{m>=1} (1 + m*q^m)^2.at n=10A022630