6915
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 11088
- Proper Divisor Sum (Aliquot Sum)
- 4173
- 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
- 3680
- Möbius Function
- -1
- Radical
- 6915
- 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
- 44
- 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 3-line partitions of n.at n=17A000991
- Expansion of 1/((1-2*x)*(1-6*x)*(1-9*x)*(1-10*x)).at n=3A026795
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 27.at n=35A031525
- Number of partitions of n into parts not of form 4k+2, 24k, 24k+9 or 24k-9. Also number of partitions in which no odd part is repeated, with at most 4 parts of size less than or equal to 2 and where differences between parts at distance 5 are greater than 1 when the smallest part is odd and greater than 2 when the smallest part is even.at n=45A036033
- Number of factorizations into distinct factors with 3 levels of parentheses indexed by prime signatures. A050349(A025487).at n=35A050350
- Number of 2 X 2 regular integer matrices with elements from {0,...,n} up to row and column permutation.at n=12A064363
- List of codewords in binary lexicode with Hamming distance 5 written as decimal numbers.at n=20A075931
- Number of ordered triples (i,j,k) with |i| + |j| + |k| <= n and gcd(i,j,k) <= 1.at n=18A100450
- Numbers k such that the k-th semiprime == 3 (mod k).at n=6A106128
- phi(n) plus the n-th prime gives a square.at n=28A116021
- Multiples of 15 containing a 15 in their decimal representation.at n=34A121035
- Numbers of the form 26+p^2 (where p is a prime).at n=22A138689
- 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), (-1, 1, 0), (1, 0, 0), (1, 1, -1)}.at n=10A148059
- 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, 0, 0), (0, -1, 1), (1, 0, -1), (1, 1, -1), (1, 1, 1)}.at n=7A149780
- Numbers k such that 30 plus the k-th triangular number is a perfect square.at n=8A154154
- Number of (n+2) X 3 binary arrays with each 3 X 3 subblock having a positive determinant.at n=4A186055
- Number of (n+2)X7 binary arrays with each 3X3 subblock having a positive determinant.at n=0A186059
- T(n,k)=Number of (n+2)X(k+2) binary arrays with each 3X3 subblock having a positive determinant.at n=10A186063
- T(n,k)=Number of (n+2)X(k+2) binary arrays with each 3X3 subblock having a positive determinant.at n=14A186063
- Values of n such that L(17) and N(17) are both prime, where L(k) = (n^2+n+1)*2^(2*k) + (2*n+1)*2^k + 1, N(k) = (n^2+n+1)*2^k + n.at n=52A227520