15390
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 40
- Divisor Sum
- 43560
- Proper Divisor Sum (Aliquot Sum)
- 28170
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 3888
- Möbius Function
- 0
- Radical
- 570
- Omega Function (Ω)
- 7
- 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
- 146
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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
- yes
- Odd
- no
Appears in sequences
- a(n) = floor(n*(n+2)*(2*n-1)/8).at n=38A007518
- Expansion of series related to Liouville's Last Theorem: g.f. sum_{t>0} (-1)^(t+1) *x^(t*(t+1)/2) / ( (1-x^t)^4 *product_{i=1..t} (1-x^i) ).at n=24A059821
- Values of m such that N=(am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,31.at n=1A064252
- Expansion of 1/(1-3x+3x^4).at n=9A090401
- Triangle read by rows: T(n,k) is the number of Dyck paths of semilength n having exactly k UDU's at low level.at n=56A098747
- Integers i such that 9*i = 25 X i, but 17*i is not 49 X i.at n=17A115811
- Numbers k such that 2*k+1, 4*k+1, 8*k+1 and 16*k+1 are primes.at n=16A124412
- a(0)=0, a(1)=1; and a(n) = a(n-1) + a(a(n-1) mod n) for n>=2.at n=49A125204
- G.f. satisfies: the coefficient of x^n in A(x)^n = 2^(n^2) for n>=1 with A(0)=1.at n=4A164764
- Number of permutations of 0..(n-1) representable as consecutive sums of 4 adjacent elements of a sequence of n+3 nonnegative integers.at n=10A180207
- E.g.f. A(x) satisfies A''(x) = 2*A(x)^3 + x*A(x) + 1.at n=11A180515
- Number of nXnXn 0..6 triangular arrays with each element x equal to the number its neighbors equal to 3,6,6,3,0,5,0 for x=0,1,2,3,4,5,6.at n=6A197660
- Number of n X n 0..2 arrays avoiding the pattern z-2 z-1 z in any row, column or nw-to-se diagonal.at n=2A207311
- Number of nX3 0..2 arrays avoiding the pattern z-2 z-1 z in any row, column or nw-to-se diagonal.at n=2A207312
- T(n,k)=Number of nXk 0..2 arrays avoiding the pattern z-2 z-1 z in any row, column or nw-to-se diagonal.at n=12A207317
- Number of (w,x,y,z) with all terms in {0,...,n}, w and x odd, y even.at n=18A212762
- The Wiener index of the ortho-polyphenyl chain with n hexagons (see the Dou et al. and the Deng references).at n=9A216108
- Numbers k such that k+1, 2k+1, 3k+1, 4k+1 are all prime.at n=7A237189
- Numbers k such that 4^k-3^(k+1) is prime.at n=17A272272
- a(n) = n*(n + 1)*(4*n + 5)/2.at n=19A281381