13315
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
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 15984
- Proper Divisor Sum (Aliquot Sum)
- 2669
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 10648
- Möbius Function
- 1
- Radical
- 13315
- Omega Function (Ω)
- 2
- 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
- 169
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- Convolution of natural numbers with Beatty sequence for the golden mean A000201.at n=35A023541
- a(1) = 5; a(n+1) = a(n)-th nonprime, where nonprimes begin at 4.at n=34A025010
- a(n) = 2^(n-1)*(3*n-4) + 3.at n=10A048496
- Number of rooted identity trees with n nodes and 3 leaves.at n=25A055328
- One half of the number of non-self-conjugate balanced partitions.at n=56A067772
- Number of numbers <= p^2 with largest prime factor <= p, where p is the n-th prime; a(0) = 1.at n=43A184677
- Number of integers in n-th generation of tree T(3/4) defined in Comments.at n=47A274146
- a(n) is the first composite number having the same base-n digits as its prime factors (with multiplicity), excluding zero digits (or 0 if no such composite number exists).at n=20A278981
- Semiprimes whose binary and ternary representations are prime when read in decimal.at n=18A279052
- a(n) is the first composite number having the same base-(2n) digits as its prime factors (with multiplicity), excluding zero digits (or 0 if no such composite number exists).at n=10A281189
- a(n) is the smallest composite number having the same base-n digits (both type and quantity) as its prime factors (with multiplicity).at n=20A281336
- Numbers k such that round(k*k^(1/k)) - round((k-1)*(k-1)^(1/(k-1))) > 1.at n=9A291210
- Number of nX7 0..1 arrays with every element unequal to 0, 1, 3 or 6 king-move adjacent elements, with upper left element zero.at n=8A304132
- Numbers k such that k and k+1 are both binary Moran numbers (A334344).at n=15A334345
- Least positive integer m relatively prime to n such that phi(m*n) = phi(m)*phi(n) is a fourth power, where phi is Euler's totient function (A000010).at n=22A334350
- Least positive integer m relatively prime to n such that phi(m*n) = phi(m)*phi(n) is a fourth power, where phi is Euler's totient function (A000010).at n=45A334350
- a(n) is the least k with k > a(n-1) such that A000120(k) = A002487(n), with a(0) = 0.at n=52A385114