15128
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 29760
- Proper Divisor Sum (Aliquot Sum)
- 14632
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7200
- Möbius Function
- 0
- Radical
- 3782
- Omega Function (Ω)
- 5
- 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
- 40
- Smith Number
- yes
- 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
- a(n) = a(n-1) + a(n-2) - 1 for n > 1, a(0)=3, a(1)=2.at n=20A001612
- a(n) = n^3 + (n+1)^3 + (n+2)^3 + (n+3)^3.at n=14A027603
- Integers that appear as ratios of Fibonacci numbers F(kn)/F(k), but omitting Fibonacci numbers F(n)/F(1) and Lucas numbers F(2n)/F(n).at n=16A031122
- a(n) = 5*F(n)^2 + 3*(-1)^n where F(n) are the Fibonacci numbers A000045.at n=10A047946
- a(n) = Fibonacci(10*n)/55.at n=3A049670
- Numbers k such that 47*2^k-1 is prime.at n=12A050549
- Larger members of g-reduced amicable pairs a < b such that sigma(a) = sigma(b) = a + b + gcd(a,b).at n=33A054572
- a(n) = Lucas(2*n) + 1.at n=10A065034
- a(0)=1, a(n) = 8*n*(2*n-1).at n=31A067239
- Numbers k that have no zero digits and such that both k+1 and (product of digits of k) + 1 are squares.at n=15A081990
- Column 2 of triangle A091602.at n=46A091605
- a(n) = Lucas(n) + (-1)^n.at n=20A099925
- Real part of absolute Gaussian perfect numbers, in order of increasing magnitude.at n=25A102531
- Numbers having three 1's in their base-phi representation.at n=11A104626
- Duplicate of A065034.at n=10A107328
- G.f.: 4th root of weight enumerator of [32,21,6] DEC extended BCH code (cf. A010463).at n=5A109476
- a(n) = 9*n^2-1.at n=40A136016
- a(0)=1; for n >= 1, a(n) = ceiling(Fibonacci(n)/a(n-1)).at n=42A140829
- a(n) = 4*(3*n+1)*(3*n+2).at n=20A144410
- Eight times hexagonal numbers: a(n) = 8*n*(2*n-1).at n=31A152750