15875
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 26
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 19968
- Proper Divisor Sum (Aliquot Sum)
- 4093
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 12600
- Möbius Function
- 0
- Radical
- 635
- Omega Function (Ω)
- 4
- 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
- 53
- Smith Number
- no
- 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
- no
- Odd
- yes
Appears in sequences
- a(n) = (4*n+1)*(4*n+3).at n=31A001539
- Numbers ending with '5' that are the difference of two positive cubes.at n=39A038860
- a(n) = (n+5)^3 - n^3.at n=30A038867
- Numbers n such that n^2 - 1 is expressible as the sum of two nonzero squares in exactly one way.at n=36A050797
- Numbers k such that sigma(k^2-k-1) = k*(k+1).at n=24A069826
- a(n)= Sum_{j=0..floor(n/2)} A073145(2*j + q), where q = 2*(n/2 - floor(n/2)).at n=32A074585
- Numbers k such that 7*10^k + 6*R_k + 3 is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=25A103065
- Products of two consecutive prime powers.at n=42A121315
- a(n) = 9*n^2-1.at n=41A136016
- a(n) = 36n^2 - 1.at n=20A136017
- 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, 0, 1), (-1, 1, 1), (1, -1, 1), (1, 0, -1), (1, 0, 1)}.at n=8A149407
- a(n) = 441*n - 1.at n=35A158319
- Irregular array read by rows in which row n lists the smallest elements, in ascending order, of conjecturally all primitive cycles of positive integers under iteration by the Collatz-like 3x-k function, where k = A226630(n).at n=36A226623
- Increasing a(n)is the smallest number of the form p^a*q^b, where a,b are positive integers and p < q are odd primes such that max( p^a, q^b)/min( p^a, q^b) <= 1 + 2/prime(n).at n=17A229108
- Number of partitions of n such that m(greatest part) = m(1), where m = multiplicity.at n=47A240078
- Numbers n such that n^2 - 1 is the average of two nonzero squares in exactly one way.at n=36A274590
- After a(0)=0, numbers n such that (A002828(1+n) = 1) and (A002828(4+n) = 4).at n=48A278491
- Least common multiple of 3*n+1 and 3*n-1.at n=42A282284
- Least common multiple of 7*n+1 and 7*n-1.at n=18A282286
- a(n) is the number of integers k in range [2^n, (2^(n+1))-1] such that all terms in finite sequence [k, floor(k/2), floor(k/4), floor(k/8), ..., 1] are squarefree.at n=31A293230