805
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 1152
- Proper Divisor Sum (Aliquot Sum)
- 347
- 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
- 528
- Möbius Function
- -1
- Radical
- 805
- Omega Function (Ω)
- 3
- 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
- 20
- Smith Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- yes
- 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
- achthundertfünf· ordinal: achthundertfünfste
- English
- eight hundred five· ordinal: eight hundred fifth
- Spanish
- ochocientos cinco· ordinal: 805º
- French
- huit cent cinq· ordinal: huit cent cinqième
- Italian
- ottocentocinque· ordinal: 805º
- Latin
- octingenti quinque· ordinal: 805.
- Portuguese
- oitocentos e cinco· ordinal: 805º
Appears in sequences
- Numbers beginning with letter 'e' in English.at n=18A000873
- a(n) = solution to the postage stamp problem with 3 denominations and n stamps.at n=20A001208
- Generalized pentagonal numbers: m*(3*m - 1)/2, m = 0, +-1, +-2, +-3, ....at n=46A001318
- Number of partitions of n into nonprime parts.at n=38A002095
- Odd squarefree numbers with an odd number of prime factors that have no prime factors greater than 31.at n=36A002556
- Second pentagonal numbers: a(n) = n*(3*n + 1)/2.at n=23A005449
- Least k such that binomial(k,n) has n or more distinct prime factors.at n=28A005733
- Expansion of x*(1+x-x^2)/((1-x)^4*(1+x)).at n=19A005744
- Number of tree-rooted toroidal maps with 3 faces and n vertices and without separating loops.at n=1A006440
- Coordination sequence T1 for Zeolite Code DAC.at n=18A008067
- Coordination sequence T6 for Zeolite Code DDR.at n=18A008076
- Coordination sequence T2 for Zeolite Code EPI.at n=18A008091
- Coordination sequence T12 for Zeolite Code MFI.at n=18A008164
- Coordination sequence T8 for Zeolite Code MFI.at n=18A008171
- Expansion of Jacobi theta constant theta_2^5 /32.at n=46A008439
- Multiples of 23.at n=35A008605
- Expansion of (1 + 2*x^2 + x^3)/((1 - x)^2*(1 - x^3)).at n=34A008822
- Coordination sequence T5 for Zeolite Code -CLO.at n=26A009854
- cosh(arcsin(x)*exp(x))=1+1/2!*x^2+6/3!*x^3+29/4!*x^4+140/5!*x^5...at n=6A012325
- Numbers k such that Phi(k,x) is a cyclotomic polynomial containing a coefficient with an absolute value greater than one.at n=43A013590