15250
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 29016
- Proper Divisor Sum (Aliquot Sum)
- 13766
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6000
- Möbius Function
- 0
- Radical
- 610
- 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
- 84
- 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
- yes
- Odd
- no
Appears in sequences
- 4-dimensional analog of centered polygonal numbers. Also number of regions created by sides and diagonals of a convex n-gon in general position.at n=26A006522
- Fibonacci sequence beginning 0, 25.at n=15A022359
- Number of partitions satisfying (cn(0,5) = 0 and cn(1,5) <= cn(2,5) and cn(1,5) <= cn(3,5) and cn(4,5) <= cn(2,5) and cn(4,5) <= cn(3,5)).at n=52A036812
- Composite numbers k such that k!/k# - 1 is prime, where k# = primorial numbers A034386.at n=25A049421
- a(n) = a(1) + a(2) + ... + a(n-1) - a(m) for n >= 4, where m = 2^(p+1) + 2 - n and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1 and a(2) = a(3) = 3.at n=15A049925
- Numbers n such that n | 5^n + 4^n + 3^n.at n=24A057236
- Numbers n that are the hypotenuse of exactly 10 distinct integer-sided right triangles, i.e., n^2 can be written as a sum of two squares in 10 ways.at n=33A097225
- Expansion of g.f. x*(-1-x-3*x^2-x^3+2*x^5)/((2*x^3+x^2-1)*(x^4+1)).at n=24A107851
- Number of base 4 circular n-digit numbers with adjacent digits differing by 1 or less.at n=10A124697
- Square array, read by antidiagonals, where row n+1 is generated from row n by first removing terms at positions [(m+3)^2/4 - 2] for m>=0 and then taking partial sums, starting with all 1's in row 0.at n=49A135878
- Numbers k such that k!/k#-1 is prime, where k# is the primorial function (A034386).at n=30A140293
- Partial sums of round(7^n/9).at n=6A156002
- a(n) = n^4 + 5*n^2 + 4.at n=11A156798
- Numbers k such that lambda(k) = lambda(k+1).at n=20A173695
- Number of n-bead necklaces labeled with numbers -3..3 allowing reversal, with sum zero and first and second differences in -3..3.at n=10A208965
- a(n) = ((sqrt(5) + 3)^n + (-sqrt(5) -1)^n + (-sqrt(5) + 3)^n + (sqrt(5) - 1)^n) / 2^n.at n=10A215500
- G.f.: exp( Sum_{n>=1} 5*L(n)*x^n/n ) where L(n) = Fibonacci(n-1)^2 + Fibonacci(n+1)^2 = A069921(n-1).at n=7A224415
- p-INVERT of (0,1,0,1,0,1,...), where p(S) = (1 - S^2) (1 - 2 S).at n=10A291239
- Positive integers that have exactly nine representations of the form 1 + p1 * (1 + p2* ... * (1 + p_j)...), where [p1, ..., p_j] is a (possibly empty) list of distinct primes.at n=26A317399
- Number of regions in a polygon whose boundary consists of n+2 equally spaced points around the arc of a semicircle. See Comments for precise definition.at n=23A333643