212
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 5
- Digital Root
- 5
- Palindromic Number
- yes
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 378
- Proper Divisor Sum (Aliquot Sum)
- 166
- 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
- 104
- Möbius Function
- 0
- Radical
- 106
- 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
- 13
- 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
- yes
- Odd
- no
Names
- German
- zweihundertzwölf· ordinal: zweihundertzwölfste
- English
- two hundred twelve· ordinal: two hundred twelfth
- Spanish
- doscientos doce· ordinal: 212º
- French
- deux cent douze· ordinal: deux cent douzième
- Italian
- duecentododici· ordinal: 212º
- Latin
- ducenti duodecim· ordinal: 212.
- Portuguese
- duzentos e doze· ordinal: 212º
Appears in sequences
- Number of dissections of an n-gon, rooted at an exterior edge, asymmetric with respect to that edge.at n=7A000150
- Number of free nonplanar polyenoids with n nodes and symmetry point group C_{2v}.at n=8A000947
- a(n) = a(n-1) + a(n-2) with a(0)=2, a(1)=5. Sometimes called the Evangelist Sequence.at n=9A001060
- Numbers k such that (k / product of digits of k) is 1 or a prime.at n=15A001103
- a(n) = floor(n*log((14/11)*n^(10/9))).at n=46A001195
- a(n) = solution to the postage stamp problem with 3 denominations and n stamps.at n=11A001208
- a(n) = solution to the postage stamp problem with n denominations and 2 stamps.at n=23A001212
- E.g.f.: 2*exp(x)/(1-x)^3.at n=3A001340
- a(n) = Sum_{k = 0..3} (n+k)! C(3,k).at n=3A001345
- Primes in ternary.at n=8A001363
- Winning moves in Fibonacci nim.at n=36A001581
- a(n) = a(n-2) + a(n-3) + a(n-4), with initial values a(0) = 0, a(1) = 2, a(2) = 3, a(3) = 6.at n=13A001634
- Numbers whose digits contain no loops (version 2).at n=56A001742
- Primes multiplied by 4.at n=15A001749
- Numbers k such that phi(k+2) = phi(k) + 2.at n=25A001838
- a(1)=2, a(2)=3; for n >= 3, a(n) is smallest number that is uniquely of the form a(j) + a(k) with 1 <= j < k < n.at n=44A001857
- Hit polynomials; convolution of natural numbers with Fibonacci numbers F(2), F(3), F(4), ....at n=8A001891
- v-pile numbers of the 3-Wythoff game with i=1.at n=49A001958
- v-pile counts for the 4-Wythoff game with i=2.at n=40A001966
- Number of partitions of n into parts 2, 3, 4, 5, 6, 7.at n=29A001996