13515
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 23328
- Proper Divisor Sum (Aliquot Sum)
- 9813
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6656
- Möbius Function
- 1
- Radical
- 13515
- 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
- 37
- 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
- a(n) = n*(n^2 + 1)/2.at n=30A006003
- First n elements of Thue-Morse sequence A010060 read as a binary number.at n=14A019300
- Number of days in n years (n=1 is the first leap year).at n=36A033174
- Replace n with concatenation of its divisors.at n=14A037278
- Replace n with concatenation of its odd divisors.at n=14A037283
- Replace n with concatenation of its odd divisors.at n=29A037283
- Replace 2n+1 with concatenation of its divisors.at n=7A037286
- Denominators of continued fraction convergents to sqrt(27).at n=5A041043
- Denominators of continued fraction convergents to sqrt(108).at n=11A041195
- Denominators of continued fraction convergents to sqrt(432).at n=11A041823
- a(n) = Sum_{1<=k<=n, gcd(k,n)=1} 2^(k-1).at n=14A054432
- Numerators of iterations of Thue-Morse sequence.at n=4A074072
- List of codewords in binary lexicode with Hamming distance 7 written as decimal numbers.at n=15A075937
- Smallest multiple of n that begins with the concatenation of the divisors of n (in increasing order).at n=14A078218
- First differences of A019300.at n=14A088172
- 33-gonal numbers: n(31n-29)/2.at n=30A098923
- Lucky numbers for which both the sum of the digits and the product of the digits is also a lucky number.at n=29A118559
- Primitive elements of A119432.at n=29A119433
- 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, -1, 0), (-1, 1, -1), (0, 0, 1), (1, -1, 1), (1, 0, -1)}.at n=11A148028
- A156977/3.at n=12A164565