638
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 1080
- Proper Divisor Sum (Aliquot Sum)
- 442
- 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
- 280
- Möbius Function
- -1
- Radical
- 638
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 3
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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 56
- Smith Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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
- sechshundertachtunddreißig· ordinal: sechshundertachtunddreißigste
- English
- six hundred thirty-eight· ordinal: six hundred thirty-eighth
- Spanish
- seiscientos treinta y ocho· ordinal: 638º
- French
- six cent trente-huit· ordinal: six cent trente-huitième
- Italian
- seicentotrentotto· ordinal: 638º
- Latin
- sescenti triginta octo· ordinal: 638.
- Portuguese
- seiscentos e trinta e oito· ordinal: 638º
Appears in sequences
- Number of free planar polyenoids with n nodes and symmetry point group C_{2v}.at n=16A000936
- a(n) = solution to the postage stamp problem with n denominations and 6 stamps.at n=6A001216
- Generalized Stirling numbers, [n+5,5]_4.at n=3A001716
- Number of nonisomorphic solutions to minimal dominating set on queens' graph Q(n).at n=7A002563
- Max_{k=0..n} { Number of partitions of n into exactly k parts }.at n=30A002569
- a(n) = 2^n - C(n,0) - ... - C(n,4).at n=10A002664
- Number of nonequivalent dissections of an n-gon into 3 polygons by nonintersecting diagonals up to rotation and reflection.at n=21A003453
- a(n) = floor(n*phi^7), where phi is the golden ratio, A001622.at n=22A004922
- a(n) = a(n-1) + a(n-8), with a(i) = 1 for i = 0..7.at n=35A005710
- a(n) = Sum_{k=0..5} binomial(n,k).at n=10A006261
- Number of fixed n-celled polyominoes which need only touch at corners.at n=4A006770
- A grasshopper sequence: closed under n -> 2n+2 and 6n+6.at n=40A007319
- Expansion of 6-dimensional cusp form (eta(q) * eta(q^3))^6 in powers of q.at n=13A007332
- Number of strict 5th-order maximal independent sets in path graph.at n=36A007385
- Number of irreducible indecomposable spherical curves with n crossings (only ordinary double points), the circle is oriented, the sphere is not oriented (OU case).at n=9A007756
- Coordination sequence T2 for Zeolite Code AFT.at n=19A008027
- Coordination sequence T2 for Zeolite Code AWW.at n=18A008046
- Coordination sequence T1 for Zeolite Code LAU.at n=18A008124
- Coordination sequence T5 for Zeolite Code MFI.at n=16A008168
- Number of orbits on points that are at n steps from 0 in D_7 lattice.at n=12A008372