999
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 27
- Digital Root
- 9
- Palindromic Number
- yes
- Repdigit
- yes
- Automorphic
- no
- Kaprekar Number
- yes
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 1520
- Proper Divisor Sum (Aliquot Sum)
- 521
- 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
- 0
- Radical
- 111
- Omega Function (Ω)
- 4
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 49
- 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
- neunhundertneunundneunzig· ordinal: neunhundertneunundneunzigste
- English
- nine hundred ninety-nine· ordinal: nine hundred ninety-ninth
- Spanish
- novecientos noventa y nueve· ordinal: 999º
- French
- neuf cent quatre-vingt-dix-neuf· ordinal: neuf cent quatre-vingt-dix-neufième
- Italian
- novecentonovantanove· ordinal: 999º
- Latin
- nongenti nonaginta novem· ordinal: 999.
- Portuguese
- novecentos e noventa e nove· ordinal: 999º
Appears in sequences
- Number of nonnegative solutions to x^2 + y^2 <= n^2.at n=35A000603
- Associated Mersenne numbers.at n=18A001351
- a(n) = 10^n - 1.at n=3A002283
- Numbers k such that (k^2 + k + 1)/19 is prime.at n=31A002643
- Number of partitions of {1..2n} that are invariant under a permutation consisting of n 2-cycles.at n=5A002872
- Smallest multiple of n whose digits sum to n.at n=27A002998
- Spiral sieve using Fibonacci numbers.at n=14A005626
- a(n) = floor(tau*a(n-1)) + a(n-2) with a(0)=0 and a(1)=2.at n=10A005829
- x^3 + n*y^3 = 1 is solvable.at n=30A005988
- Number of entries in first n rows of Pascal's triangle not divisible by 3.at n=73A006048
- Kaprekar numbers: positive numbers n such that n = q+r and n^2 = q*10^m+r, for some m >= 1, q >= 0 and 0 <= r < 10^m, with n != 10^a, a >= 1.at n=7A006886
- Noncircumscribable simplicial polyhedra with n nodes.at n=11A007034
- Number of P-graphs with 2n edges.at n=5A007164
- Coordination sequence T6 for Zeolite Code MFI.at n=20A008169
- Coordination sequence T2 for Zeolite Code MTN.at n=19A008187
- Molien series for 4-dimensional complex reflection group of order 7680 (in powers of x^4).at n=51A008669
- Expansion of (1+x^5)/((1-x)*(1-x^2)*(1-x^3)*(1-x^4)).at n=39A008766
- Coordination sequence T2 for Zeolite Code -ROG.at n=24A009860
- Repdigit numbers, or numbers whose digits are all equal.at n=27A010785
- Numbers > 9 with all digits the same.at n=17A014181