644
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 1344
- Proper Divisor Sum (Aliquot Sum)
- 700
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- yes
Derived Values
- Euler's Totient
- 264
- Möbius Function
- 0
- Radical
- 322
- Omega Function (Ω)
- 4
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 100
- 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
- sechshundertvierundvierzig· ordinal: sechshundertvierundvierzigste
- English
- six hundred forty-four· ordinal: six hundred forty-fourth
- Spanish
- seiscientos cuarenta y cuatro· ordinal: 644º
- French
- six cent quarante-quatre· ordinal: six cent quarante-quatrième
- Italian
- seicentoquarantaquattro· ordinal: 644º
- Latin
- sescenti quadraginta quattuor· ordinal: 644.
- Portuguese
- seiscentos e quarenta e quatro· ordinal: 644º
Appears in sequences
- Number of discordant permutations.at n=4A000561
- Perrin sequence (or Perrin numbers, or Ondrej Such sequence): a(n) = a(n-2) + a(n-3) with a(0) = 3, a(1) = 0, a(2) = 2.at n=23A001608
- Numbers n such that every digit contains a loop (version 2).at n=56A001744
- Generalized sum of divisors function.at n=22A002132
- Numbers k such that the k-th tetrahedral number is the sum of 2 tetrahedral numbers.at n=22A002311
- The square sieve.at n=44A002960
- Numbers k such that 2*3^k - 1 is prime.at n=18A003307
- Numbers that are the sum of 5 positive 4th powers.at n=40A003339
- Numbers that are the sum of 9 positive 7th powers.at n=5A003376
- Simple triangulations of a disk: column 4 of square array in A210664.at n=4A004305
- Numbers that are the sum of at most 9 positive 7th powers.at n=44A004871
- Numbers that are the sum of at most 10 positive 7th powers.at n=49A004872
- Numbers that are the sum of at most 11 positive 7th powers.at n=54A004873
- a(n) = round(n*phi^12), where phi is the golden ratio, A001622.at n=2A004947
- a(n) = ceiling(n*phi^12), where phi is the golden ratio, A001622.at n=2A004967
- Certain subgraphs of a directed graph.at n=3A005330
- Number of n-step self-avoiding walks on hexagonal lattice from (0,0) to (2,2).at n=3A005553
- Number of Twopins positions.at n=15A005689
- a(n) = binomial(n+3,6) + binomial(n+1,5) + binomial(n,5).at n=5A005732
- Number of paraffins.at n=13A005998