13125
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 20
- Divisor Sum
- 24992
- Proper Divisor Sum (Aliquot Sum)
- 11867
- 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
- 105
- Omega Function (Ω)
- 6
- 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
- 76
- 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
- Numbers that are the sum of 9 positive 7th powers.at n=45A003376
- Numbers that are the sum of 5 nonzero 8th powers.at n=11A003383
- Expansion of (1-x^5) / (1-x)^5.at n=25A008487
- Numbers k that divide s(k), where s(1)=1, s(j)=21*s(j-1)+j.at n=33A014872
- Scaled Chebyshev U-polynomial evaluated at sqrt(5)/2.at n=7A030191
- One fifth of deca-factorial numbers.at n=3A035274
- Truncated square pyramid numbers: a(n) = Sum_{k = n..2*n-1} k^2.at n=18A050410
- Numbers k such that 199*2^k-1 is prime.at n=38A050851
- 24-gonal numbers: a(n) = n*(11*n-10).at n=35A051876
- Coefficient triangle of polynomials (falling powers) related to Fibonacci convolutions. Companion triangle to A057282.at n=28A057281
- Triangle of coefficients of polynomials (rising powers) useful for convolutions of A000032(n+1), n >= 0 (Lucas numbers).at n=12A061188
- a(n) = 21*n^2.at n=25A064762
- Numbers k such that the product of the digits of k is equal to the sum of the prime factors of k, counted with multiplicity.at n=30A065774
- Numbers k such that S(k)=d(k), where S(k) is the Kempner function (A002034) and d(k) is the number of divisors of k (A000005).at n=14A073307
- Numbers n such that number of divisors of n divides S(n), the Kempner function A002034.at n=25A073413
- Triangle read by rows: T(n,k), n >=1, 0 <= k <= C(n,k), = number of n X n symmetric positive definite matrices with 2's on the main diagonal and 1's and 0's elsewhere and with k 1's above the diagonal.at n=55A080858
- Square array of binomial transforms of Fibonacci numbers, read by antidiagonals.at n=63A081576
- Square array T(n,k) of second binomial transforms of generalized Fibonacci numbers, read by ascending antidiagonals, with n, k >= 0.at n=53A083861
- Binomial transform of A084624.at n=10A084625
- Numerator of Product_{2 <= p < 2*n} (2*n - p)/p.at n=23A084762