5815
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 6984
- Proper Divisor Sum (Aliquot Sum)
- 1169
- 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
- 4648
- Möbius Function
- 1
- Radical
- 5815
- 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
- 142
- 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
- Number of n-node rooted trees of height 4.at n=13A000299
- Numbers k such that 9*2^k - 1 is prime.at n=23A002236
- Shifts one place left under 3rd-order binomial transform.at n=6A004212
- s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = (Lucas numbers), t = A001950 (upper Wythoff sequence).at n=17A024475
- s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (Lucas numbers), t = A001950 (upper Wythoff sequence).at n=16A025095
- 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 15.at n=39A031513
- Numbers which, when expressed as a sum of distinct primes with maximum product, use a non-maximal number of primes.at n=23A053020
- a(n) = 4*n^2 - 7*n + 4.at n=38A054567
- a(n) = n^3 - n + 1.at n=18A061600
- The last number for which a determinant of base-n numbers is nonzero.at n=16A079505
- G.f.: 1/Product_{k>0} (1-x^k)^A000669(k+1).at n=9A106606
- Triangle, generated from A111579.at n=48A111673
- Semiprimes in A054567.at n=16A113692
- a(n) = 2*a(n-1) + a(n-2) - a(n-3) + a(n-4), with a(1) = 0, a(2) = 3, a(3) = 5 and a(4) = 17.at n=10A130844
- 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, 1, 1), (1, -1, -1), (1, 0, -1)}.at n=8A148879
- Numbers k such that 3^k + 3^4 + 1 is prime.at n=14A168170
- Numbers k such that sum_{i=1..k} d(i)^2 is a square c^2, where d(i) is the number of divisors of i.at n=10A186429
- Concentric 17-gonal numbers.at n=37A195047
- Concentric 19-gonal numbers.at n=35A195048
- a(n) = 16*n^2 + 2*n + 1.at n=19A204675