15879
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 30
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 21760
- Proper Divisor Sum (Aliquot Sum)
- 5881
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 10296
- Möbius Function
- -1
- Radical
- 15879
- 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
- 146
- 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
- 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 84.at n=27A031582
- Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 84.at n=2A031762
- Composites c whose decimal expansion ends with its largest prime factor.at n=38A050693
- Draw a line through every pair of points with coordinates (x, 1) and (x', 2) with x, x' in 1..n, and then count the number of intersection points above the line y = 2.at n=21A092275
- t(n)_n where t() = triangular numbers A000217.at n=41A122634
- a(n) = (2*n + 1)*(5*n + 6).at n=39A153127
- a(n) = A168174(n)-10^12.at n=21A168248
- Numbers k such that, taken together, the base-10 and base-b expansions of k are pandigital for some b < 10.at n=0A174596
- Numbers k such that Sum_{d|k} sigma(d)^3/d is an integer, where d are the divisors of k.at n=8A226566
- Numbers n such that n = concatenate(a, b) and sigma(a) + sigma(b) = sigma(n) - n.at n=7A239562
- Numbers k such that (17*10^k - 89)/9 is prime.at n=16A295324
- a(n) = Sum_{k=1..n} k * tau(k)^2, where tau is A000005.at n=36A320896
- Numbers k whose ordered binary weights (A000120) of their divisors are the numbers 1 to A000005(k).at n=44A354724