218
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 11
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 330
- Proper Divisor Sum (Aliquot Sum)
- 112
- 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
- 108
- Möbius Function
- 1
- Radical
- 218
- 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
- 114
- 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
- yes
- Odd
- no
Names
- German
- zweihundertachtzehn· ordinal: zweihundertachtzehnste
- English
- two hundred eighteen· ordinal: two hundred eighteenth
- Spanish
- doscientos dieciocho· ordinal: 218º
- French
- deux cent dix-huit· ordinal: deux cent dix-huitième
- Italian
- duecentodiciotto· ordinal: 218º
- Latin
- ducenti duodeviginti· ordinal: 218.
- Portuguese
- duzentos e dezoito· ordinal: 218º
Appears in sequences
- Numbers k such that (2k)^4 + 1 is prime.at n=53A000059
- Partial sums of (unordered) ways of making change for n cents using coins of 1, 2, 5, 10 cents.at n=18A000064
- Denumerants: Expansion of 1/((1-x)*(1-x^2)*(1-x^5)).at n=62A000115
- Number of partitions into non-integral powers.at n=7A000158
- Number of unlabeled simple digraphs with n nodes.at n=4A000273
- Number of positive integers <= 2^n of form 2 x^2 + 5 y^2.at n=10A000286
- a(n) = Sum_{k=0..n} (-1)^(n-k)*binomial(n,k)*2^(2^k).at n=3A000371
- Restricted permutations.at n=6A000382
- Related to population of numbers of form x^2 + y^2.at n=9A000694
- Numbers k such that sum of squares of k consecutive integers >= 1 is a square.at n=26A001032
- a(n) = floor(n*log((14/11)*n^(10/9))).at n=47A001195
- Expansion of 1/((1-x)^2*(1-x^2)*(1-x^5)*(1-x^10)*(1-x^20)).at n=18A001305
- Number of ways of making change for n cents using coins of 1, 2, 4, 10, 20, 40, 100 cents.at n=37A001310
- Number of ways of making change for n cents using coins of 1, 2, 4, 10, 20, 40, 100 cents.at n=36A001310
- a(1) = 1; thereafter a(n+1) = floor(sqrt(2*a(n)*(a(n)+1))).at n=14A001521
- Winning moves in Fibonacci nim.at n=37A001581
- Numbers k such that 3^k, 3^(k+1) and 3^(k+2) have the same number of digits.at n=10A001682
- 2 together with primes multiplied by 2.at n=29A001747
- a(n) = floor((n+2/3)*(5+sqrt(13))/2); v-pile positions in the 3-Wythoff game.at n=50A001960
- v-pile positions of the 4-Wythoff game with i=3.at n=41A001968