13559
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
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 16800
- Proper Divisor Sum (Aliquot Sum)
- 3241
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 10656
- Möbius Function
- -1
- Radical
- 13559
- Omega Function (Ω)
- 3
- 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
- 89
- 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
- Graham-Sloane-type lower bound on the size of a ternary (n,3,9) constant-weight code.at n=4A030509
- Pair the odd numbers such that the k-th pair is (r, r+2k) where r is the smallest odd number not included earlier: (1, 3), (5, 9), (7, 13), (11, 19), (15, 25), (17, 29), (21, 35), (23, 39), (27, 45), ... This is the sequence of the product of the members of pairs.at n=28A075320
- Numbers k such that 2^k + prime(k) is prime.at n=24A077375
- Sum of the primes in ordered 3 X 3 prime squares.at n=26A105089
- Numbers k such that either 2^k + prime(k) or 2^k - prime(k) is prime.at n=39A130640
- Triangle read by rows: T2[n,k] = Sum_{partitions of n with k parts p(n, k; m_1, m_2, m_3, ..., m_n)} c(n; m_1, m_2, ..., m_n) * x_1^m_1 * x_2^m_2 * ... x^n*m_n, where x_i = i-th prime.at n=23A145520
- a(n) = 3*A022004(n) + 8.at n=36A163635
- Number of ways to place 2 nonattacking kings on an n X n cylindrical chessboard.at n=12A194650
- Number of 3 X n 0..1 arrays with rows nondecreasing and antidiagonals unimodal.at n=25A224134
- Number of partitions of n for which (number of occurrences of the least part) < (number of occurrences of greatest part).at n=54A236545
- MM-numbers of labeled graphs with loops spanning an initial interval of positive integers.at n=23A320461
- MM-numbers of labeled multigraphs with loops spanning an initial interval of positive integers.at n=41A320462
- a(n) = Sum_{i=1..n} phi(i)*phi(i+1), where phi(n) = A000010(n) is Euler's totient function.at n=48A330319
- a(n) = (n - 1)*n*(2*n^2 + 4*n - 1)/6.at n=14A330700