2031
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 6
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 2712
- Proper Divisor Sum (Aliquot Sum)
- 681
- 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
- 1352
- Möbius Function
- 1
- Radical
- 2031
- 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
- 63
- Smith Number
- no
- Vampire 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
Appears in sequences
- Centered pentagonal numbers: (5n^2+5n+2)/2; crystal ball sequence for 3.3.3.4.4. planar net.at n=28A005891
- Number of paraffins.at n=20A005999
- a(n) = 3 + n/2 + 7*n^2/2.at n=24A006124
- Expansion of (1+x^7)/((1-x)*(1-x^2)*(1-x^3)*(1-x^4)).at n=51A008768
- a(n) = Sum_{k=0..n} T(k) where T(n) are the tribonacci numbers A000073.at n=13A008937
- Super-3 Numbers (3n^3 contains substring '333' in its decimal expansion).at n=15A014569
- Define the generalized Pisot sequence T(a(0),a(1)) by: a(n+2) is the greatest integer such that a(n+2)/a(n+1) < a(n+1)/a(n). This is T(4,8).at n=10A018921
- Numbers k such that Fibonacci(k) == -2 (mod k).at n=32A023163
- Binary expansion contains a single 0.at n=51A030130
- Numbers whose base-4 representation has 4 fewer 0's than 3's.at n=16A031469
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 15.at n=15A031513
- Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 15.at n=2A031693
- Lucky numbers with size of gaps equal to 8 (upper terms).at n=22A031891
- Numbers whose set of base-5 digits is {1,3}.at n=46A032912
- Multiplicity of highest weight (or singular) vectors associated with character chi_147 of Monster module.at n=38A034535
- a(1)=1, a(n) = smallest odd number such that all sums of pairs of (not necessarily distinct) terms in the sequence are distinct.at n=27A034757
- Decimal expansion of a(n) is given by the first n terms of the periodic sequence with initial period 2,0,3,1.at n=3A037729
- Maximal base 5 run length is 4.at n=21A037983
- Coordination sequence T13 for Zeolite Code STT.at n=30A038420
- Sums of 10 distinct powers of 2.at n=6A038461