581
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
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 672
- Proper Divisor Sum (Aliquot Sum)
- 91
- 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
- 492
- Möbius Function
- 1
- Radical
- 581
- 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
- 118
- Smith Number
- 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
Classification
- Even
- no
- Odd
- yes
Names
- German
- fünfhunderteinundachtzig· ordinal: fünfhunderteinundachtzigste
- English
- five hundred eighty-one· ordinal: five hundred eighty-first
- Spanish
- quinientos ochenta y uno· ordinal: 581º
- French
- cinq cent quatre-vingt-un· ordinal: cinq cent quatre-vingt-unième
- Italian
- cinquecentoottantuno· ordinal: 581º
- Latin
- quingenti octoginta unus· ordinal: 581.
- Portuguese
- quinhentos e oitenta e um· ordinal: 581º
Appears in sequences
- Number of centered 3-valent (or boron, or binary) trees with n nodes.at n=15A000675
- Number of twin prime pairs < square of n-th prime.at n=44A000885
- A self-generating sequence: a(1)=1, a(2)=2, a(n+1) chosen so that a(n+1)-a(n-1) is the first number not obtainable as a(j)-a(i) for 1<=i<j<=n.at n=28A001149
- Partial sums of A001462; also a(n) is the last occurrence of n in A001462.at n=60A001463
- Expansion of 1/((1+x)*(1-x)^5).at n=10A001752
- a(n+1) = 1 + a( floor(n/1) ) + a( floor(n/2) ) + ... + a( floor(n/n) ).at n=18A003318
- Numbers that are the sum of 6 positive 4th powers.at n=43A003340
- Add 4, then reverse digits; start with 0.at n=35A003608
- a(n) = round(n*phi^7), where phi is the golden ratio, A001622.at n=20A004942
- a(n) = ceiling(n*phi^7), where phi is the golden ratio, A001622.at n=20A004962
- Record values in A005210.at n=26A005211
- Number of symmetric plane partitions of n.at n=22A005987
- a(n) = n*(n + 1)*(2*n^2 + 2*n - 1)/6.at n=5A006324
- Number of n-node forests not determined by their spectra.at n=11A006611
- Add 8, then reverse digits!.at n=31A007399
- Poincaré series [or Poincare series] of Lie algebra associated with a certain braid group.at n=8A007991
- Coordination sequence T3 for Zeolite Code EMT.at n=20A008088
- Coordination sequence T1 for Zeolite Code LTN.at n=17A008140
- Coordination sequence T2 for Zeolite Code LTN.at n=17A008141
- Increasing length runs of consecutive composite numbers (records).at n=49A008996