15216
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 20
- Divisor Sum
- 39432
- Proper Divisor Sum (Aliquot Sum)
- 24216
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 5056
- Möbius Function
- 0
- Radical
- 1902
- Omega Function (Ω)
- 6
- 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
- 32
- 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 nonnegative solutions to x^2 + y^2 + z^2 <= n^2.at n=30A000604
- Number of graphs with n edges.at n=11A000664
- Site percolation series for square lattice.at n=20A006731
- a(n) = A027082(n, 2n-1).at n=10A027088
- a(n) = |{m : multiplicative order of 7 mod m=n}|.at n=23A059889
- Numbers n such that [A070080(n), A070081(n), A070082(n)] is an acute integer triangle with integer area.at n=31A070146
- Numbers k such that sigma(phi(k)) = k-phi(k).at n=4A070171
- Using the US English names for the nonnegative integers, assign each letter a numerical value as in A073327 (A=1, B=2, ..., Z=26), treat the name as a base-27 integer, and convert to decimal.at n=2A072959
- Duplicate of A072959.at n=2A087096
- Number of partitions of n which represent first player winning Chomp positions with unique winning moves.at n=38A112472
- Indices n such that the 3 X 3 matrix with components (row by row) prime(n+k), 0 <= k <= 8, has zero determinant.at n=20A117345
- Numbers k such that k and k^2 use only the digits 1, 2, 3, 5 and 6.at n=43A136974
- a(n) = P_{2n}(sqrt(2))/sqrt(2) (see A155100).at n=3A156122
- a(n) = ((1+4*sqrt(2))*(4+sqrt(2))^n + (1-4*sqrt(2))*(4-sqrt(2))^n)/2.at n=5A164300
- The number of squarefree permutations of 1,...,n.at n=9A221989
- Numbers k such that 10^k + prime(k) is prime.at n=7A256451
- Numbers k such that the decimal expansions of both k and k^2 have 1 as smallest digit and 6 as largest digit.at n=20A257197
- Triangle, read by rows, T(n,k) = k*Sum_{i=0..(n-k)/2} C(k,i)*C(2*n-k-4*i-1,n-2*i-k)/(n-2*i).at n=57A257558
- Numbers n such that n^3+prime(n) and n^3-prime(n) are prime.at n=34A257788
- Number of 3 X n 0..2 arrays with no element equal to any value at offset (-2,-2) (-1,-2) or (0,-1) and new values introduced in order 0..2.at n=8A275143