13405
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
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 18432
- Proper Divisor Sum (Aliquot Sum)
- 5027
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 9168
- Möbius Function
- -1
- Radical
- 13405
- 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
- 138
- 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
- Numbers k such that binomial(2k,k)+1 is prime.at n=36A066699
- 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, -1), (-1, -1, 1), (0, 0, 1), (0, 1, -1), (1, 0, 1)}.at n=8A150036
- Products of 3 distinct safe primes.at n=34A157354
- Number of -7..7 arrays of n elements with first and second differences also in -7..7.at n=3A201087
- T(n,k)=Number of -k..k arrays of n elements with first and second differences also in -k..k.at n=48A201088
- Number of -n..n arrays of 4 elements with first and second differences also in -n..n.at n=6A201089
- G.f.: Sum_{n>=0} x^n * Product_{k=1..n} (1+x^k)/(1-x^k).at n=24A207641
- Number of (n+1) X (1+1) 0..3 arrays with the maximum plus the upper median minus the lower median of every 2 X 2 subblock differing from its horizontal and vertical neighbors by exactly one.at n=2A238293
- Number of (n+1)X(3+1) 0..3 arrays with the maximum plus the upper median minus the lower median of every 2X2 subblock differing from its horizontal and vertical neighbors by exactly one.at n=0A238295
- T(n,k) = Number of (n+1) X (k+1) 0..3 arrays with the maximum plus the upper median minus the lower median of every 2 X 2 subblock differing from its horizontal and vertical neighbors by exactly one.at n=3A238298
- T(n,k) = Number of (n+1) X (k+1) 0..3 arrays with the maximum plus the upper median minus the lower median of every 2 X 2 subblock differing from its horizontal and vertical neighbors by exactly one.at n=5A238298
- Expansion of (x/(8 * (1-x))) * d/dx(theta_3(x)^4).at n=31A374535
- The number of pairs of 3x3 matrices with elements from 0 to n such that the matrix product results in each element being the concatenation of the corresponding terms in base n.at n=7A375157