8405
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 10338
- Proper Divisor Sum (Aliquot Sum)
- 1933
- 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
- 6560
- Möbius Function
- 0
- Radical
- 205
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 34
- 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
- Numbers k such that k | 4^k + 1.at n=10A015950
- Numbers k that divide 4^k + 1, k not a power of 5.at n=4A015974
- a(n) = 5*n^2.at n=41A033429
- Numbers whose base-7 representation contains exactly four 3's.at n=16A043408
- Numbers k that divide 8^k + 2^k.at n=26A045581
- Composite numbers k such that sigma(k) / d(k) is prime.at n=13A048969
- a(n)=T(n,n+3), array T as in A049735.at n=35A049743
- Numbers k such that 7^k == -1 (mod k-1).at n=13A055690
- Indices of primes in sequence defined by A(0) = 11, A(n) = 10*A(n-1) + 31 for n > 0.at n=4A056245
- Least number starting a chain of exactly 2n-1 consecutive integers that do not have totient inverses.at n=6A063512
- Numbers from A066112 that are neither square nor twice a square, i.e., are not in A028982 but are in A028983.at n=31A066134
- Numbers k such that sigma(core(k)) = tau(k) where core(k) is the squarefree part of k, tau(k) is the number of divisors of k, and sigma(k) is their sum.at n=45A069827
- Sum of all terms on the two principal diagonals of a 2n+1 X 2n+1 square spiral.at n=11A114254
- Numbers k such that binomial(6k, k) + 1 is prime.at n=18A125245
- (k^2)-th k-smooth number for k = prime(n).at n=14A133581
- The sum of the principal diagonals of an n X n spiral.at n=23A137930
- (0=0, 1=1, 2=2, 3=3, 4=2^2, 5=5, 6=2*3, 7=7, 8=2^3, 9=3^2, 10=2*5, 11=11, 12=2^2*3, ...) becomes (0*0*1, 1*2*2, 3*3*4, 2*2*5, 5*6*2, 3*7*7, 8*2*3, 9*3*2, 10*2*5, 11*11*12, 2*2*3, ...).at n=39A144153
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, 0, 0), (0, -1, 0), (0, 1, -1), (0, 1, 0), (1, 0, 1)}.at n=7A150559
- Integer averages of halves of first cubes of natural numbers (n^3)/2 for some n.at n=14A164579
- Period of decimal representation of 1/n^3.at n=40A176921