15159
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 20992
- Proper Divisor Sum (Aliquot Sum)
- 5833
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 9720
- Möbius Function
- -1
- Radical
- 15159
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 133
- 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
- Number of permutations of (1,...,n) having n-5 inversions (n>=5).at n=7A005283
- 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 82.at n=28A031580
- Numbers whose base-5 representation contains exactly three 1's and three 4's.at n=16A045262
- 2-ranks of difference sets constructed from Glynn type II hyperovals.at n=13A049114
- 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, 0), (-1, 0, 0), (-1, 0, 1), (1, -1, -1), (1, 1, 0)}.at n=9A149095
- Number of reduced words of length n in the Weyl group A_11.at n=7A161459
- Auxiliary r(n) sequence used to prove some properties about Rowland's sequence: r(1) = 1, and r(n) = 1/2*(c(n)+1), where c(n) is A190894, for n>1.at n=36A190895
- The continued fraction of the constant r > sqrt(3) such that the partial quotients equal the integer floor of the powers of r.at n=17A227233
- Mahonian numbers T(n,7) (cf. A008302).at n=7A242657
- Numbers k such that k![6]-2 is prime, where k![6] = A085158 (k) = sextuple factorial.at n=36A283485
- List of numbers k whose consecutive digits increase or decrease by d-1, where d is the number of digits in k.at n=83A292439
- Numbers k such that (109*10^k + 17)/9 is prime.at n=16A294910
- a(n) = n^n - Sum_{k=1..n-2} f_k(n), with f_k(n)=( floor( (n^n - Sum_{t=1..k-1} f_t(n))^(1/(n-k)) ) )^(n-k).at n=50A349184