819
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 1456
- Proper Divisor Sum (Aliquot Sum)
- 637
- 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
- 432
- Möbius Function
- 0
- Radical
- 273
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 3
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
- 41
- Smith Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- Prime Power
- no
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Names
- German
- achthundertneunzehn· ordinal: achthundertneunzehnste
- English
- eight hundred nineteen· ordinal: eight hundred nineteenth
- Spanish
- ochocientos diecinueve· ordinal: 819º
- French
- huit cent dix-neuf· ordinal: huit cent dix-neufième
- Italian
- ottocentodiciannove· ordinal: 819º
- Latin
- octingenti undeviginti· ordinal: 819.
- Portuguese
- oitocentos e dezenove· ordinal: 819º
Appears in sequences
- a(n) = n*(n+3)/2.at n=39A000096
- Square pyramidal numbers: a(n) = 0^2 + 1^2 + 2^2 + ... + n^2 = n*(n+1)*(2*n+1)/6.at n=13A000330
- Number of partitions of n into prime parts.at n=50A000607
- Numbers beginning with letter 'e' in English.at n=32A000873
- Number of cells of square lattice of edge 1/n inside quadrant of unit circle centered at 0.at n=32A001182
- Double-bitters: only even length runs in binary expansion.at n=21A001196
- The coding-theoretic function A(n,4,4).at n=24A001843
- Number of dissections of a polygon: binomial(7n,n)/(6n+1).at n=4A002296
- Divisors of 2^12 - 1.at n=21A003524
- Divisors of 2^24 - 1.at n=34A003532
- Divisors of 2^36 - 1.at n=54A003543
- Divisors of 2^48 - 1.at n=41A003553
- a(n) = least integer m > a(n-1) such that m - a(n-1) != a(j) - a(k) for all j, k less than n; a(1) = 1, a(2) = 2.at n=28A004978
- a(n) = n*(5*n+1)/2.at n=18A005475
- a(n) = a(n-1) + a(n-7), with a(i) = 1 for i = 0..6.at n=33A005709
- a(n) = (n + 1)*(n + 2)*(n + 4)*(n + 8)*(n + 15)/120.at n=5A006636
- a(n) = binomial(n+3, 3)/4 for odd n, n*(n+2)*(n+4)/24 for even n.at n=25A006918
- Binary palindromes: numbers whose binary expansion is palindromic.at n=56A006995
- Number of lattice points inside circle of radius n is 4(a(n)+n)-3.at n=32A007882
- Expansion of (1-x)/(1-2*x+x^2-2*x^3).at n=11A007909