8165
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
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 10368
- Proper Divisor Sum (Aliquot Sum)
- 2203
- 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
- 6160
- Möbius Function
- -1
- Radical
- 8165
- 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
- 65
- 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
- Row 3 of array in A047666.at n=22A047667
- Discriminants of real quadratic fields with class number 2 and related continued fraction period length of 8.at n=38A051973
- a(n) = 2^n - (2*n+1).at n=13A070313
- pi(n) is a power of 2, where pi(n) = A000720(n) is the number of primes <= n.at n=41A073798
- Products of Wythoff pairs: [n*r]*[n*r^2], where [] is the floor function and r is the golden ratio, (1+sqrt(5))/2.at n=43A075312
- a(n) = sum of n-th row of the triangle pertaining to A079774(n).at n=45A079776
- Greedy frac multiples of 1/Pi: a(1)=1, Sum_{n>0} frac(a(n)*x) = 1 at x=1/Pi, where "frac(y)" denotes the fractional part of y.at n=29A080142
- a(n) = ceiling(((1*n^0 + 1*n^1 + 2*n^2 + 4*n^3)/(1*n^0 + 2*n^1 + 1*n^2))^2).at n=23A085505
- Numbers n where |sinc(n)| decreases monotonically to 0 (where sinc(x)=sin(x)/x).at n=48A131975
- Numbers whose square starts with 4 identical digits.at n=6A132391
- 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, -1, 0), (-1, 1, 1), (0, 1, 0), (1, 0, 1), (1, 1, -1)}.at n=7A150297
- 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, -1, -1), (0, 0, 1), (0, 1, 0), (1, 0, 1), (1, 1, 1)}.at n=6A151248
- a(1) = 1, and for each k >=2, a(k) is the smallest number n such that n/sin(n) > a(k)/sin(a(k)), so that a(1)/sin(a(1)) > a(2)/sin(a(2)) > ... > a(k)/sin(a(k)) > ...at n=25A172445
- a(n) = 12*n^2 + 2*n + 1.at n=26A194454
- Number of n-node simple graphs having clique number 8.at n=10A205577
- a(n) = 2^n - 27.at n=13A220087
- Table read by antidiagonals of numbers of form (2^n - 1)*2^(m+3) + 5 where n>=1, m>=1.at n=43A224701
- Number of partitions of n such that some part is a sum of two other parts.at n=33A237113
- Triangle read by rows: T(n,k) is the number of unlabeled simple graphs on n vertices with independence number k.at n=62A263341
- Triangle read by rows, T(n, k) = S(k, n) with S(n, n) = 1, S(0, n) = 0 and otherwise S(k,n) = Sum_{i=1..n-k+1} k^i*S(k-1, n-i), for n>=0 and 0<=k<=n.at n=33A269955