213
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 6
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 288
- Proper Divisor Sum (Aliquot Sum)
- 75
- 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
- 140
- Möbius Function
- 1
- Radical
- 213
- 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
- 13
- 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
- zweihundertdreizehn· ordinal: zweihundertdreizehnste
- English
- two hundred thirteen· ordinal: two hundred thirteenth
- Spanish
- doscientos trece· ordinal: 213º
- French
- deux cent treize· ordinal: deux cent treizième
- Italian
- duecentotredici· ordinal: 213º
- Latin
- ducenti tredecim· ordinal: 213.
- Portuguese
- duzentos e treze· ordinal: 213º
Appears in sequences
- Coefficients of ménage hit polynomials.at n=6A000222
- Number of steps to reach 1 in sequence A000546.at n=40A000547
- Genus of complete graph on n nodes.at n=53A000933
- Expansion of 1/((1-x)^2*(1-x^2)*(1-x^5)).at n=19A001304
- Number of ways of making change for n cents using coins of 1, 2, 4, 10 cents.at n=38A001362
- Number of ways of making change for n cents using coins of 1, 2, 4, 10 cents.at n=39A001362
- Nearest integer to 2*n*log(n).at n=31A001618
- Squares written in base 6.at n=9A001741
- Numbers whose digits contain no loops (version 2).at n=57A001742
- a(n) = 3 * prime(n).at n=19A001748
- Sorting numbers: number of comparisons for merge insertion sort of n elements.at n=48A001768
- Sorting numbers: maximal number of comparisons for sorting n elements by binary insertion.at n=45A001855
- a(n) = floor((n+2/3)*(5+sqrt(13))/2); v-pile positions in the 3-Wythoff game.at n=49A001960
- v-pile positions of the 4-Wythoff game with i=3.at n=40A001968
- Class numbers of quadratic fields.at n=7A001985
- Least number k such that phi(k) = m, where m runs through the values (A002202) taken by phi.at n=52A002181
- Number of integral points in a certain sequence of open quadrilaterals.at n=23A002578
- a(n) = Sum_{d|n, d <= 4} d^2 + 4*Sum_{d|n, d>4} d.at n=52A002791
- Numbers m such that 6m-1, 6m+1 are twin primes.at n=41A002822
- Number of simple perfect squared rectangles of order n up to symmetry.at n=12A002839