2108
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 11
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 4032
- Proper Divisor Sum (Aliquot Sum)
- 1924
- 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
- 960
- Möbius Function
- 0
- Radical
- 1054
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 81
- Smith Number
- no
- Vampire 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
Appears in sequences
- Numbers of the form (p^2 - 49)/120 where p is prime.at n=47A002382
- Number of partitions of n into parts 5k+2 or 5k+3.at n=62A003106
- Number of walks of length 2n+7 in the path graph P_8 from one end to the other.at n=4A005023
- Number of partitions of 2n with all subsums different from n.at n=17A006827
- Number of golygons of order 8n (or serial isogons of order 8n).at n=2A007219
- a(0) = 1, a(n) = 26*n^2 + 2 for n>0.at n=9A010016
- Exponential convolution of Catalan numbers with themselves.at n=6A014330
- Numbers n such that phi(n + 9) | sigma(n) for n not congruent to 0 (mod 3).at n=36A015849
- Index of 7^n within the sequence of the numbers of the form 3^i*7^j.at n=48A025721
- a(n) = (n + 3)^2 - 8.at n=43A028884
- 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 22.at n=34A031520
- Triangle of numbers of connected regular (k X n)-matrix matroids of dimension k.at n=61A034327
- Number of matroids: column 6 of A034327.at n=11A034332
- Number of binary [ n,4 ] codes.at n=11A034358
- Number of binary [ n,8 ] codes.at n=11A034362
- Dirichlet convolution of triangular numbers with themselves.at n=33A034715
- Number of partitions satisfying cn(0,5) <= cn(1,5) and cn(0,5) <= cn(4,5).at n=27A039837
- Numerators of continued fraction convergents to sqrt(561).at n=6A042074
- Base-5 palindromes that start with 3.at n=21A043008
- Numbers n such that string 7,4 occurs in the base 8 representation of n but not of n-1.at n=36A044247