99
domain: N
Properties
Digital Properties
- Digit Count
- 2
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- yes
- Repdigit
- yes
- Automorphic
- no
- Kaprekar Number
- yes
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 156
- Proper Divisor Sum (Aliquot Sum)
- 57
- 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
- 60
- Möbius Function
- 0
- Radical
- 33
- Omega Function (Ω)
- 3
- 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
- 25
- Smith Number
- no
Classification
- Natural
- yes
- Even
- no
- Odd
- yes
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
Names
- German
- neunundneunzig· ordinal: neunundneunzigste
- English
- ninety-nine· ordinal: ninety-ninth
- Spanish
- noventa y nueve· ordinal: 99º
- French
- quatre-vingt-dix-neuf· ordinal: quatre-vingt-dix-neufième
- Italian
- novantanove· ordinal: 99º
- Latin
- nonaginta novem· ordinal: 99.
- Portuguese
- noventa e nove· ordinal: 99º
Appears in sequences
- Numbers that are not squares (or, the nonsquares).at n=89A000037
- 1-digit numbers arranged in alphabetical order, then the 2-digit numbers arranged in alphabetical order, then the 3-digit numbers, etc.at n=49A000052
- Numbers k such that (2k)^4 + 1 is prime.at n=28A000059
- Maximal number of regions obtained by joining n points around a circle by straight lines. Also number of regions in 4-space formed by n-1 hyperplanes.at n=7A000127
- Number of partitions into non-integral powers.at n=5A000160
- a(8i+j) = 13i + a(j), where 1<=j<=8.at n=60A000202
- A Beatty sequence: floor(n*(e-1)).at n=57A000210
- 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=52A000379
- Numbers that are the sum of three nonzero squares.at n=65A000408
- Numbers that are the sum of 3 but no fewer nonzero squares.at n=41A000419
- Number of permutations of [n] in which the longest increasing run has length 5.at n=6A000456
- a(n) = 4*n^2 - 1.at n=5A000466
- Number of nonnegative solutions to x^2 + y^2 + z^2 <= n^2.at n=5A000604
- Number of nonnegative solutions to x^2 + y^2 + z^2 <= n.at n=25A000606
- Expansion of Product_{k >= 1} (1 - x^k)^6.at n=56A000729
- Number of compositions of n into 3 ordered relatively prime parts.at n=17A000741
- Numbers ending with a vowel in American English.at n=46A000861
- Number of primes < prime(n)^2.at n=8A000879
- Number of free nonplanar polyenoids with n nodes and symmetry point group C_s.at n=3A000948
- Lucky numbers.at n=22A000959