2215
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 10
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 2664
- Proper Divisor Sum (Aliquot Sum)
- 449
- 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
- 1768
- Möbius Function
- 1
- Radical
- 2215
- 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
- 120
- 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=18A001549
- Number of non-Abelian metacyclic groups of order 2^n.at n=42A007982
- Coordination sequence T1 for Zeolite Code BIK.at n=28A008047
- Coordination sequence T3 for Zeolite Code GOO.at n=32A008113
- a(n) = least m such that if r and s in {1/1, 1/4, 1/7,..., 1/(3n-2)} satisfy r < s, then r < k/m < s for some integer k.at n=31A024822
- Sums of five consecutive squares: a(n) = n^2 + (n+1)^2 + (n+2)^2 + (n+3)^2 + (n+4)^2.at n=19A027578
- Numbers k such that the continued fraction for sqrt(k) has even period 2*m and the m-th term of the periodic part is 9.at n=25A031412
- Sequence (a(n): n >= 1) that shifts left 2 places under the "CIK" (necklace, indistinct, unlabeled) transform and satisfies a(1) = a(2) = 1.at n=13A032202
- Coordination sequence T5 for Zeolite Code STF.at n=31A038440
- Sums of 3 distinct powers of 3.at n=38A038465
- Number of partitions satisfying cn(1,5) + cn(4,5) <= cn(0,5) + cn(2,5) + cn(3,5).at n=28A039866
- Denominators of continued fraction convergents to sqrt(421).at n=8A041801
- a(n)=(s(n)+6)/9, where s(n)=n-th base 9 palindrome that starts with 3.at n=23A043074
- Numbers whose base-13 representation has exactly 4 runs.at n=4A043659
- Numbers k such that string 4,7 occurs in the base 8 representation of k but not of k-1.at n=38A044226
- Numbers k such that string 3,1 occurs in the base 9 representation of k but not of k-1.at n=30A044279
- Numbers n such that string 1,5 occurs in the base 10 representation of n but not of n-1.at n=25A044347
- Numbers n such that string 2,4 occurs in the base 8 representation of n but not of n+1.at n=39A044588
- Numbers n such that string 4,7 occurs in the base 8 representation of n but not of n+1.at n=38A044607
- Numbers n such that string 3,1 occurs in the base 9 representation of n but not of n+1.at n=30A044660