2043
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 9
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 2964
- Proper Divisor Sum (Aliquot Sum)
- 921
- 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
- 1356
- Möbius Function
- 0
- Radical
- 681
- Omega Function (Ω)
- 3
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 156
- 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
- no
- Odd
- yes
Appears in sequences
- Record values in A005210.at n=49A005211
- Coordination sequence T4 for Zeolite Code MEL.at n=29A008153
- Coordination sequence T3 for Zeolite Code -ROG.at n=34A009861
- Numbers k such that Fib(k) == -34 (mod k).at n=18A023169
- Sum of remainders of n mod prime(k), for k = 1,2,3,...,n.at n=51A024925
- a(1) = 7; a(n+1) = a(n)-th nonprime, where nonprimes begin at 1.at n=21A025006
- (d(n)-r(n))/5, where d = A026046 and r is the periodic sequence with fundamental period (1,0,4,0,0).at n=27A026048
- a(n) = (d(n)-r(n))/5, where d = A026057 and r is the periodic sequence with fundamental period (1,0,3,1,0).at n=32A026059
- a(n) = A027082(n, 2n-1).at n=8A027088
- Numbers k that divide the (right) concatenation of all numbers <= k written in base 21 (most significant digit on left).at n=51A029466
- 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 5.at n=41A031408
- Least term in period of continued fraction for sqrt(n) is 5.at n=11A031429
- Numbers whose base-4 representation has 4 fewer 0's than 3's.at n=18A031469
- Number of partitions of n into parts not of the form 19k, 19k+4 or 19k-4. Also number of partitions with at most 3 parts of size 1 and differences between parts at distance 8 are greater than 1.at n=27A035973
- Number of partitions of n such that cn(0,5) = cn(2,5) < cn(1,5) <= cn(3,5) = cn(4,5).at n=66A036856
- Sums of 10 distinct powers of 2.at n=8A038461
- If n has decimal expansion abc...d, with k digits, let f(n) be obtained by deleting all k's from abc...d, closing up and deleting initial 0's; sequence gives n such that f(f(f(...(n)))) = 0 or empty.at n=39A038528
- Base 8 palindromes that start with 3.at n=17A043023
- Numbers having four 3's in base 4.at n=26A043348
- Numbers k such that string 7,3 occurs in the base 8 representation of k but not of k-1.at n=35A044246