815
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 984
- Proper Divisor Sum (Aliquot Sum)
- 169
- 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
- 648
- Möbius Function
- 1
- Radical
- 815
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 134
- Smith Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- achthundertfünfzehn· ordinal: achthundertfünfzehnste
- English
- eight hundred fifteen· ordinal: eight hundred fifteenth
- Spanish
- ochocientos quince· ordinal: 815º
- French
- huit cent quinze· ordinal: huit cent quinzième
- Italian
- ottocentoquindici· ordinal: 815º
- Latin
- octingenti quindecim· ordinal: 815.
- Portuguese
- oitocentos e quinze· ordinal: 815º
Appears in sequences
- Numbers beginning with letter 'e' in English.at n=28A000873
- A Fielder sequence.at n=10A001643
- a(n) = a(n-1) + a(n-2) + a(n-3), a(0)=3, a(1)=1, a(2)=3.at n=11A001644
- Primes multiplied by 5.at n=37A001750
- Numbers k such that 33*2^k - 1 is prime.at n=23A002240
- Numbers k such that (k^2 + k + 1)/13 is prime.at n=39A002642
- Arrays of dumbbells.at n=4A002889
- Expansion of 1/((1-2*x)*(1-x-2*x^3)).at n=8A003478
- a(n) = 3*n^2 + 3*n - 1.at n=16A004538
- Number of unlabeled reduced unit interval graphs on n nodes.at n=11A005218
- Parenthesized one way gives the powers of 2: (1), (2), (1+3), ..., another way the powers of 3: (1), (2+1), (3+6), ....at n=18A006895
- Erroneous version of A182322.at n=7A007174
- Coordination sequence T2 for Zeolite Code LOV.at n=19A008135
- Coordination sequence T2 for Zeolite Code LTN.at n=20A008141
- "Pascal sweep" for k=9: draw a horizontal line through the 1 at C(k,0) in Pascal's triangle; rotate this line and record the sum of the numbers on it (excluding the initial 1).at n=13A009540
- Coordination sequence T1 for Zeolite Code ZON.at n=20A009919
- Numbers k such that the continued fraction for sqrt(k) has period 12.at n=40A020351
- Pisot sequences E(6,8), P(6,8).at n=17A020716
- Expansion of Product_{m>=1} (1+x^m)^10.at n=4A022575
- a(n) = [ (2n+2)/(n-1) ] + [ (2n+4)/(n-2) ] + ... + [ (4n-2)/1 ].at n=50A022824