2811
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 3752
- Proper Divisor Sum (Aliquot Sum)
- 941
- 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
- 1872
- Möbius Function
- 1
- Radical
- 2811
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 58
- 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
- Related to Gilbreath conjecture.at n=20A001549
- Squares written in base 9.at n=45A002442
- Coordination sequence T2 for Zeolite Code MTT.at n=33A008190
- Coordination sequence T4 for Zeolite Code SGT.at n=33A008232
- Least d such that period of continued fraction for sqrt(d) contains n (n^2+2 if n odd, (n/2)^2+1 if n even).at n=52A013945
- Convolution of A023531 and Lucas numbers.at n=16A023558
- Number of 5's in all partitions of n.at n=29A024789
- Number of partitions of n into an even number of parts.at n=30A027187
- 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 53.at n=0A031551
- Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 53.at n=0A031731
- Nonprime; becomes prime if any digit is deleted (zeros not allowed in the number).at n=38A034304
- Number of inequivalent binary [ n,3 ] codes of dimension <= 3 without zero columns.at n=21A034337
- Positive numbers having the same set of digits in base 5 and base 7.at n=42A037430
- Numerators of continued fraction convergents to sqrt(421).at n=4A041800
- Numbers k such that the string 6,3 occurs in the base 9 representation of k but not of k-1.at n=38A044308
- Numbers n such that string 1,1 occurs in the base 10 representation of n but not of n-1.at n=28A044343
- Numbers n such that string 6,3 occurs in the base 9 representation of n but not of n+1.at n=38A044689
- Numbers n such that string 1,1 occurs in the base 10 representation of n but not of n+1.at n=28A044724
- Numbers whose base-4 representation contains exactly three 2's and three 3's.at n=2A045151
- Number of cycle types of conjugacy classes of all even permutations of n elements.at n=30A046682