38
domain: N
Properties
Digital Properties
- Digit Count
- 2
- 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
- 60
- Proper Divisor Sum (Aliquot Sum)
- 22
- 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
- 18
- Möbius Function
- 1
- Radical
- 38
- 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
- 21
- Smith Number
- no
Classification
- Natural
- yes
- Even
- yes
- Odd
- 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
Names
- German
- achtunddreißig· ordinal: achtunddreißigste
- English
- thirty-eight· ordinal: thirty-eighth
- Spanish
- treinta y ocho· ordinal: 38º
- French
- trente-huit· ordinal: trente-huitième
- Italian
- trentotto· ordinal: 38º
- Latin
- triginta octo· ordinal: 38.
- Portuguese
- trinta e oito· ordinal: 38º
Appears in sequences
- Expansion of Product_{m >= 1} (1 + x^m); number of partitions of n into distinct parts; number of partitions of n into odd parts.at n=17A000009
- Mosaic numbers or multiplicative projection of n: if n = Product (p_j^k_j) then a(n) = Product (p_j * k_j).at n=37A000026
- The positive integers. Also called the natural numbers, the whole numbers or the counting numbers, but these terms are ambiguous.at n=37A000027
- Numbers that are not squares (or, the nonsquares).at n=31A000037
- Generalized tangent numbers d(n,1).at n=18A000061
- A Beatty sequence: a(n) = floor(n/(e-2)).at n=27A000062
- Odious numbers: numbers with an odd number of 1's in their binary expansion.at n=19A000069
- Number of transformation groups of order n.at n=36A000113
- Related to zeros of Bessel function.at n=4A000175
- Number of bicentered hydrocarbons with n atoms.at n=10A000200
- Lower Wythoff sequence (a Beatty sequence): a(n) = floor(n*phi), where phi = (1+sqrt(5))/2 = A001622.at n=23A000201
- a(8i+j) = 13i + a(j), where 1<=j<=8.at n=23A000202
- a(n) = sigma(n), the sum of the divisors of n. Also called sigma_1(n).at n=36A000203
- Coefficients of ménage hit polynomials.at n=5A000222
- Number of n-node rooted trees of height 3.at n=7A000235
- a(n) = a(n-1) + a(n-2)^3.at n=6A000280
- From a fractal set of positive Lebesgue measure, a self-replicating tiling with holes, the 4-reptile following the 2-reptile of Paul Levy.at n=37A000361
- Genocchi numbers of second kind (A005439) divided by 2^(n-1).at n=4A000366
- Topswops (1): start by shuffling n cards labeled 1..n. If top card is m, reverse order of top m cards, then repeat. a(n) is the maximal number of steps before top card is 1.at n=9A000375
- Topswops (2): start by shuffling n cards labeled 1..n. If the top card is m, reverse the order of the top m cards. Repeat until 1 gets to the top, then stop. Suppose the whole deck is now sorted (if not, discard this case). a(n) is the maximal number of steps before 1 got to the top.at n=9A000376