6815
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
- 8640
- Proper Divisor Sum (Aliquot Sum)
- 1825
- 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
- 5152
- Möbius Function
- -1
- Radical
- 6815
- 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
- 181
- 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
- a(n) = dot_product(1,2,...,n)*(6,7,...,n,1,2,3,4,5).at n=23A026046
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 11 ones.at n=14A031779
- Trajectory of 3 under map n->33n+1 if n odd, n->n/2 if n even.at n=7A037114
- Denominators of continued fraction convergents to sqrt(591).at n=9A042133
- Base-6 palindromes that start with 5.at n=23A043014
- Numbers k such that the smoothly undulating palindromic number (74*10^k - 47)/99 is a prime.at n=3A062223
- Number of incongruent ways to tile a 5 X 2n room with 1x2 Tatami mats. At most 3 Tatami mats may meet at a point.at n=36A068930
- Sum of first n 4-almost primes.at n=40A086046
- Number of partitions of the n-th decimal palindrome into distinct decimal palindromes.at n=36A091585
- a(n) = n*(8*n+3).at n=29A139276
- a(n) = n*(3*n + 4).at n=47A140676
- a(n) = A142590(n)/3.at n=47A142883
- Number of cubefree integers not exceeding 2^n.at n=13A160113
- a(n) is the only number m such that m = pi(1^(1/n)) + pi(2^(1/n)) + ... + pi(m^(1/n)).at n=7A171270
- Numbers n such that 10^n - 77 is prime.at n=17A178436
- Number of -3..3 arrays x(i) of n+1 elements i=1..n+1 with x(i)+x(j), x(i+1)+x(j+1), -(x(i)+x(j+1)), and -(x(i+1)+x(j)) having one or three distinct values for every i<=n and j<=n.at n=7A211499
- Number of n X 5 0..2 arrays with rows nondecreasing and antidiagonals unimodal.at n=2A224009
- T(n,k)=Number of nXk 0..2 arrays with rows nondecreasing and antidiagonals unimodal.at n=23A224012
- Number of 3 X n 0..2 arrays with rows nondecreasing and antidiagonals unimodal.at n=4A224013
- Nonprime terms in A210494.at n=11A230214