85
domain: N
Properties
Digital Properties
- Digit Count
- 2
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 108
- Proper Divisor Sum (Aliquot Sum)
- 23
- 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
- 64
- Möbius Function
- 1
- Radical
- 85
- 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
- 9
- Smith Number
- yes
Classification
- Natural
- yes
- Even
- no
- Odd
- yes
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
Names
- German
- fünfundachtzig· ordinal: fünfundachtzigste
- English
- eighty-five· ordinal: eighty-fifth
- Spanish
- ochenta y cinco· ordinal: 85º
- French
- quatre-vingt-cinq· ordinal: quatre-vingt-cinqième
- Italian
- ottantacinque· ordinal: 85º
- Latin
- octoginta quinque· ordinal: 85.
- Portuguese
- oitenta e cinco· ordinal: 85º
Appears in sequences
- Numbers that are not squares (or, the nonsquares).at n=75A000037
- 1-digit numbers arranged in alphabetical order, then the 2-digit numbers arranged in alphabetical order, then the 3-digit numbers, etc.at n=13A000052
- Lower Wythoff sequence (a Beatty sequence): a(n) = floor(n*phi), where phi = (1+sqrt(5))/2 = A001622.at n=52A000201
- A Beatty sequence: floor(n*(e-1)).at n=49A000210
- a(n) = floor(n^2/3).at n=16A000212
- Take sum of squares of digits of previous term; start with 5.at n=3A000221
- 3*n - 2*floor(sqrt(4*n+5)) + 5.at n=34A000277
- Numbers m such that Fibonacci(m) ends with m.at n=9A000350
- Numbers where total number of 1-bits in the exponents of their prime factorization is even; a 2-way classification of integers: complement of A000028.at n=43A000379
- Numbers that are the sum of 2 nonzero squares.at n=29A000404
- Numbers that are the sum of 2 but no fewer nonzero squares.at n=28A000415
- Differences of reciprocals of unity.at n=1A000424
- The greedy sequence of integers which avoids 3-term geometric progressions.at n=62A000452
- Unsigned Stirling numbers of first kind s(n,4).at n=2A000454
- 1 together with products of 2 or more distinct primes.at n=29A000469
- Numbers that are the sum of 2 squares but not sum of 3 nonzero squares.at n=17A000549
- A Beatty sequence: [ n(e+1) ].at n=22A000572
- Number of nonnegative solutions of x^2 + y^2 = z in first n shells.at n=41A000592
- Number of 4-colored labeled graphs on n nodes, divided by 4.at n=2A000686
- Moser-de Bruijn sequence: sums of distinct powers of 4.at n=15A000695