8570
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 15444
- Proper Divisor Sum (Aliquot Sum)
- 6874
- 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
- 3424
- Möbius Function
- -1
- Radical
- 8570
- 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
- 171
- 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
- yes
- Odd
- no
Appears in sequences
- Numbers k such that the continued fraction for sqrt(k) has period 25.at n=27A020364
- Number of partitions satisfying cn(0,5) + cn(2,5) < cn(1,5) + cn(4,5) and cn(0,5) + cn(3,5) < cn(1,5) + cn(4,5).at n=34A039885
- Numbers k such that 9*10^k + R_k is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=9A056726
- G.f.: (1 + Sum_{ i >= 0 } 2^i*x^(2^(i+1)-1)) / (1-x)^3.at n=39A063916
- Number of ways of pairing the odd squares of the numbers 1 to n with the even squares of the numbers n+1 to 2n such that each pair sums to a prime.at n=26A077763
- Octo numbers (a polygonal sequence): a(n) = 5*n^2 - 6*n + 2 = (n-1)^2 + (2*n-1)^2.at n=41A079273
- Diagonal in array of n-gonal numbers A081422.at n=19A081438
- 47-gonal numbers.at n=19A095311
- Numbers n such that sigma(n)=2n-phi(phi(n)).at n=11A110073
- Determinant of n X n matrix of first n^2 terms of Kolakoski sequence (A000002).at n=34A119493
- Number of partitions of n such that if k is the largest part, then k-2 occurs as a part.at n=40A119907
- Number of cycles in range [A014137(n-1)..A014138(n-1)] of permutation A127387.at n=10A127385
- Triangle read by rows: A007318^(-1) * A136536.at n=72A136537
- a(n) = 250*n - 180.at n=35A154360
- Number of binary strings of length n with equal numbers of 0000 and 0001 substrings.at n=14A164147
- First result not divisible by 4 when iterating k -> k+tau(k) from 2(2n-1)^2.at n=32A165495
- a(n) = (11*n^2 + 11*n - 20)/2.at n=38A166144
- a(n) = Sum_{k=0..n} A109613(k)*A005843(n-k).at n=29A171218
- Numbers that are the product of 3 distinct primes a,b and c, such that a^2+b^2+c^2 is the average of a twin prime pair.at n=38A176879
- Number of 4-bead necklaces labeled with numbers -n..n not allowing reversal, with sum zero and first differences in -n..n.at n=28A208995