4209
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 5952
- Proper Divisor Sum (Aliquot Sum)
- 1743
- 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
- 2640
- Möbius Function
- -1
- Radical
- 4209
- Omega Function (Ω)
- 3
- 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
- 33
- Smith Number
- yes
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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
- a(n) is the number of conjugacy classes in the alternating group A_n.at n=31A000702
- a(n) = (10n+1)*(10n+9).at n=6A001535
- a(n) = (d(n)-r(n))/5, where d = A026049 and r is the periodic sequence with fundamental period (4,1,4,0,1).at n=35A026051
- 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 42.at n=28A031540
- Concatenations C1 and C2 are both prime (see the comment lines).at n=44A034816
- a(n) = smallest number which is not the sum of exactly 1 or a(n-1) earlier terms.at n=16A035334
- Digit sum of 'odd' number equals digit sum of 'sum' and 'juxtaposition' of its prime factors (counted with multiplicity).at n=27A036927
- Denominators of continued fraction convergents to sqrt(406).at n=8A041771
- Numerators of continued fraction convergents to sqrt(613).at n=6A042176
- Numbers having three 1's in base 8.at n=41A043427
- Numbers k such that the string 0,9 occurs in the base 10 representation of k but not of k-1.at n=45A044341
- Numbers whose base-4 representation contains exactly three 0's and three 1's.at n=26A045031
- Sizes of successive clusters in Z^4 lattice.at n=29A046895
- Odd numbers not of the form 3 + twin prime + twin prime.at n=35A051345
- n for which floor((4/3)^n) is prime.at n=27A070762
- Number of permutations satisfying -k<=p(i)-i<=r and p(i)-i not in I, i=1..n, with k=1, r=4, I={3}.at n=14A079975
- Diagonal of table A083362.at n=45A083363
- Numbers k such that 10^k + 13 is prime.at n=12A095688
- First differences of A052911.at n=7A100059
- Row sums of triangular matrix A105540, in which column n equals A105540^(n+1) when flattened as read by rows.at n=16A105541