639
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 936
- Proper Divisor Sum (Aliquot Sum)
- 297
- 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
- 420
- Möbius Function
- 0
- Radical
- 213
- 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
- 131
- 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
- no
- Odd
- yes
Names
- German
- sechshundertneununddreißig· ordinal: sechshundertneununddreißigste
- English
- six hundred thirty-nine· ordinal: six hundred thirty-ninth
- Spanish
- seiscientos treinta y nueve· ordinal: 639º
- French
- six cent trente-neuf· ordinal: six cent trente-neufième
- Italian
- seicentotrentanove· ordinal: 639º
- Latin
- sescenti triginta novem· ordinal: 639.
- Portuguese
- seiscentos e trinta e nove· ordinal: 639º
Appears in sequences
- Number of ways of making change for n cents using coins of 1, 2, 4, 12, 24, 48, 96, 120 cents (based on English coinage of 1939).at n=57A001364
- Number of ways of making change for n cents using coins of 1, 2, 4, 12, 24, 48, 96, 120 cents (based on English coinage of 1939).at n=56A001364
- Expansion of 1/(1-x)^2/(1-x^2)/(1-x^6)/(1-x^12)/(1-x^24)/(1-x^48)/(1-x^60).at n=28A001365
- Numbers of the form (p^2 - 49)/120 where p is prime.at n=28A002382
- a(n) = Sum_{k=0..n} binomial(n,k)^2 * binomial(2*k,k).at n=4A002893
- a(n) = round(n*phi^7), where phi is the golden ratio, A001622.at n=22A004942
- a(n) = ceiling(n*phi^7), where phi is the golden ratio, A001622.at n=22A004962
- In the '3x+1' problem, these values for the starting value set new records for highest point of trajectory before reaching 1.at n=8A006884
- Oscillates under partition transform.at n=25A007211
- Number of triangles with integer sides and area = n times perimeter.at n=32A007237
- McKay-Thompson series of class 4D for the Monster group.at n=4A007249
- Number of 5th-order maximal independent sets in path graph.at n=36A007380
- Les Marvin sequence: a(n) = F(n) + (n-1)*F(n-1), F() = Fibonacci numbers.at n=10A007502
- Sum of the first n primes.at n=20A007504
- Tower of Hanoi with 5 pegs.at n=43A007665
- Number of immersions of the unoriented circle into the oriented plane with n double points.at n=5A008981
- Coordination sequence T2 for Zeolite Code -CHI.at n=16A009847
- a(0) = 1, a(n) = 13*n^2 + 2 for n>0.at n=7A010004
- a(n) = 2*a(n-2) + 1.at n=14A010737
- a(n) = floor( n*(n-1)*(n-2)/19 ).at n=24A011901