13685
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 23
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 20736
- Proper Divisor Sum (Aliquot Sum)
- 7051
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8448
- Möbius Function
- 1
- Radical
- 13685
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 4
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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 58
- 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
- Square pyramidal numbers: a(n) = 0^2 + 1^2 + 2^2 + ... + n^2 = n*(n+1)*(2*n+1)/6.at n=34A000330
- a(n) = (6*n+1)*(6*n+5).at n=19A001513
- Coefficient of x^4 in (1-x-x^2)^(-n).at n=19A006504
- Odd square pyramidal numbers.at n=17A015221
- Numbers whose sum of divisors is a fourth power.at n=36A019422
- Pseudoprimes to base 13.at n=36A020141
- Number of partitions of n into parts of 20 kinds.at n=4A023018
- a(n) = s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n-k+1), where k = floor(n/2), s = (odd natural numbers).at n=33A025112
- a(n) = T(n,n+3), T given by A027023.at n=11A027025
- Numerators of continued fraction convergents to sqrt(950).at n=11A042838
- Terms of A050530 with four prime divisors.at n=4A053340
- Consider the line segment in R^n from the origin to the point P=(1,2,3,...,n); let d = squared distance to this line from the closest point of Z^n (excluding the endpoints). Sequence gives d times P.P.at n=33A059774
- Sum of numbers in n-th upward diagonal of triangle in A079823.at n=44A079824
- a(n) = (4*n+3)*(4*n+7).at n=28A085027
- a(n) = n^3 + 6*n^2 + 6*n + 1.at n=22A090197
- Terms of A094302 without repetition.at n=27A094426
- Sequence and first differences include all square numbers exactly once.at n=33A109678
- Ceiling(4*Pi*n^2).at n=32A135971
- a(1)=1, a(n)=a(n-1)+n if n odd, a(n)=a(n-1)+ n^2 if n is even.at n=41A140113
- Second trisection of A061037.at n=38A142599