5515
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 6624
- Proper Divisor Sum (Aliquot Sum)
- 1109
- 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
- 4408
- Möbius Function
- 1
- Radical
- 5515
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 160
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- Convolution inverse of A143348.at n=10A002039
- Cycle class sequence c(2n) (the number of true cycles of length 2n in which a certain node is included) for zeolite PAU = Paulingite (K2,Ca,Na2)76[Al152Si520O1344] starting with a T5 atom.at n=5A019053
- Numbers k such that the continued fraction for sqrt(k) has period 58.at n=39A020397
- a(n) = p(1)p(n) + p(2)p(n-1) + ... + p(k)p(n+1-k), where k = [ (n+1)/2 ], p = A000040 = the primes.at n=19A024697
- a(n) = p(1)p(n) + p(2)p(n-1) + ... + p(k)p(n-k+1), where k = [ n/2 ], p = A000040, the primes.at n=19A025129
- Numbers having three 5's in base 10.at n=11A043511
- Numbers k such that 2^k - k^2 is prime.at n=21A072180
- a(n) is the number of subsets of {1,...,n} containing no solutions to x+y=z with x and y distinct (one version of "sum-free subsets").at n=17A085489
- Near-repdigit semiprimes with 5 as repeated digit.at n=19A105986
- a(n) = A108466(A025487).at n=34A108467
- Numbers m such that (15m-4, 15m-2, 15m+2, 15m+4) is a prime quadruple.at n=33A112540
- Smaller of two consecutive semiprimes with the same digital root.at n=35A118699
- Euler transform of A141199.at n=8A144791
- Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 0110-0100-1111 pattern in any orientation.at n=15A146795
- 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), (-1, 0, 1), (0, 0, -1), (1, 0, -1), (1, 1, 1)}.at n=7A149723
- The second of a pair of sequences A and B with property that all the differences |a_i - b_j| are distinct - for precise definition see Comments lines in A169677.at n=36A169678
- The initial decimal digits of 2^a(n) are the decimal digits of n followed by n.at n=14A171652
- Number of distinct solutions of sum{i=1..2}(x(2i-1)*x(2i)) = 1 (mod n), with x() in 0..n-1.at n=37A180804
- Numbers k such that (7*10^(2*k+1)+18*10^k-7)/9 is prime.at n=9A183183
- Triangle of coefficients of polynomials u(n,x) jointly generated with A210863; see the Formula section.at n=48A210862