8520
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
- 32
- Divisor Sum
- 25920
- Proper Divisor Sum (Aliquot Sum)
- 17400
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 2240
- Möbius Function
- 0
- Radical
- 2130
- Omega Function (Ω)
- 6
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 78
- 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
- yes
- Odd
- no
Appears in sequences
- Number of strict 5th-order maximal independent sets in path graph.at n=51A007385
- Number of lines through exactly 6 points of an n X n grid of points.at n=50A018813
- Numbers k such that A102489(k) is divisible by k.at n=34A032563
- a(n) = a(n-1) + a(m) for n >= 4, where m = 2^(p+1) + 2 - n and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1, a(2) = 2, and a(3) = 4.at n=46A050053
- Numbers k such that phi(x) = k has exactly 11 solutions.at n=29A060674
- Numbers k such that sigma(k)+1 is a square and sets a new record for such squares.at n=31A063729
- Values of m such that N = (am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,3.at n=40A064238
- Numbers m such that N=(am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,19.at n=1A064246
- Aliquot sequence starting at 1521.at n=7A074906
- Differences between two successive prime powers of prime numbers (A076707) in more than one way.at n=27A077257
- Differences between two successive powers of a prime but not a prime (A025475) in more than one way.at n=27A077274
- Integers that occur more than once as the difference of the squares of two consecutive primes.at n=35A078667
- Local maxima of A053707 (first differences of A025475, powers of a prime but not prime).at n=42A088365
- a(n) = round(n^3/12) - floor(n/4)*floor((n+2)/4).at n=47A090676
- Numbers that can be expressed as the difference of the squares of consecutive primes in just two distinct ways.at n=32A090784
- Numbers that can be expressed as the difference of the squares of primes in exactly four distinct ways.at n=21A092000
- Triangle read by rows: T(n,k) is the number of stacks of n pancakes requiring k = 0, ..., A058986(n) flips to sort.at n=43A092113
- Numbers k such that if P = 10*k^2+1, then P, P+6, P+12 and P+18 are all primes.at n=28A092446
- a(n) = ((n^3 - 4n + 1)*A000166(n) + (-1)^(n+1)*(n-1)^2) / 6.at n=6A105928
- Numbers that are the least element of a k-cycle (k > 1) of permutation A113821.at n=15A115641