8645
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 23
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 13440
- Proper Divisor Sum (Aliquot Sum)
- 4795
- 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
- 5184
- Möbius Function
- 1
- Radical
- 8645
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 4
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
- 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
- Number of partitions into non-integral powers.at n=16A000339
- a(n) = (6*n+1)*(6*n+5).at n=15A001513
- 4-dimensional figurate numbers: a(n) = (6*n-2)*binomial(n+2,3)/4.at n=12A002419
- a(n) = n*(n+1)*(n+2)*(n+7)/24.at n=19A005582
- Define the sequence T(a(0),a(1)) by a(n+2) is the greatest integer such that a(n+2)/a(n+1) < a(n+1)/a(n) for n >= 0. This is T(6,37).at n=4A022035
- a(n) = s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n+1-k), where k = [ (n+1)/2 ], s = (composite numbers).at n=31A024588
- n written in fractional base 10/8.at n=35A024663
- s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n-k+1), where k = [ n/2 ], s = (composite numbers).at n=30A025102
- Odd numbers to the left of the central elements of the (1,2)-Pascal triangle A029635.at n=54A029646
- Odd numbers to the right of the central elements of the (2,1)-Pascal triangle A029653 that are different from 1.at n=32A029668
- Pisot sequence L(7,8).at n=21A048588
- Pisot sequence L(8,10).at n=20A048591
- Values of e, the lesser key or generating number for Pythagorean triangles in which S (the odd short leg) and U (the hypotenuse) are twin primes.at n=30A051892
- Terms of A050530 with four prime divisors.at n=1A053340
- Composite numbers k with no prime factor among (2, 3) (cf. A038509) and such that phi(k) < 2*k/3.at n=27A069043
- Integers which have at least two different factorizations into coprime parts whose sum are equal.at n=35A069064
- One-sixth the area of the smallest primitive d-arithmetic triangle, where d=A072330(n).at n=27A072360
- a(n) = (2*n+5)*(2*n+1).at n=45A078371
- Numbers k such that binomial(prime(k), k) is divisible by k^2.at n=26A081384
- Antidiagonal sums of table A083362.at n=25A083364