1365
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 2688
- Proper Divisor Sum (Aliquot Sum)
- 1323
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 576
- Möbius Function
- 1
- Radical
- 1365
- 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
- 13
- 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
- Binomial coefficient binomial(n,4) = n*(n-1)*(n-2)*(n-3)/24.at n=15A000332
- Euler's "numerus idoneus" (or "numeri idonei", or idoneal, or suitable, or convenient numbers).at n=63A000926
- Expansion of g.f. (1 + x + 2*x^2)/((1 - x)^2*(1 - x^3)).at n=44A000969
- a(2n) = 2*a(2n-1), a(2n+1) = 2*a(2n)+1 (also a(n) is the n-th number without consecutive equal binary digits).at n=11A000975
- Jacobsthal sequence (or Jacobsthal numbers): a(n) = a(n-1) + 2*a(n-2), with a(0) = 0, a(1) = 1; also a(n) = nearest integer to 2^n/3.at n=12A001045
- Generalized octagonal numbers: k*(3*k-2), k=0, +- 1, +- 2, +-3, ...at n=42A001082
- a(n) = sigma_2(n): sum of squares of divisors of n.at n=31A001157
- a(n) = binomial(n,11).at n=4A001288
- a(n) = a(n-1) + a(n-2) - 1 for n > 1, a(0)=3, a(1)=2.at n=15A001612
- Tetranacci numbers A073817 without the leading term 4.at n=10A001648
- Triangular numbers plus quarter-squares: n*(n+1)/2 + floor((n+1)^2/4) (i.e., A000217(n) + A002620(n+1)).at n=42A001859
- Denominators of cosecant numbers: -2*(2^(2*n-1)-1)*Bernoulli(2*n).at n=6A001897
- Denominators of cosecant numbers: -2*(2^(2*n-1)-1)*Bernoulli(2*n).at n=12A001897
- a(n) = (4^n - 1)/3.at n=6A002450
- Odd squarefree numbers with an even number of prime factors that have no prime factors greater than 31.at n=47A002557
- Divisors of 2^12 - 1.at n=22A003524
- Divisors of 2^24 - 1.at n=38A003532
- Degrees of irreducible representations of alternating group A_13.at n=16A003868
- Degrees of irreducible representations of symmetric group S_13.at n=30A003877
- Degrees of irreducible representations of symmetric group S_13.at n=29A003877