15518
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 23280
- Proper Divisor Sum (Aliquot Sum)
- 7762
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7758
- Möbius Function
- 1
- Radical
- 15518
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 146
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- yes
- Odd
- no
Appears in sequences
- a()=A037260 and its first [ A037261 ], 2nd [ A037262 ] and 3rd [ A037263 ] differences together include every number at most once and are monotonic and minimal.at n=20A037260
- a(n) = a(1) + a(2) + ... + a(n-1) + a(m) for n >= 4, where m = 2*n - 2 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1, a(2) = 2, and a(3) = 3.at n=13A049959
- a(n) = 49*n^2 - 20*n + 2.at n=17A157373
- Row sums of A163334 and A163336 divided by 6.at n=43A163479
- Column sums of an infinite Kostka matrix.at n=95A182395
- G.f. satisfies A(x) = exp( Sum_{n>=1} (A(x^n) + A(-x^n))/2 * x^n/n ).at n=21A195865
- Number of -n..n arrays x(0..2) of 3 elements with nonzero sum and with zero through 2 differences all nonzero.at n=12A200166
- Number of 0..7 arrays x(0..n+1) of n+2 elements with zero n-1st differences.at n=20A200271
- Number of (n+1) X (n+1) -10..10 symmetric matrices with every 2 X 2 subblock having sum zero and two distinct values.at n=14A211813
- G.f.: A(x) = exp( Sum_{n>=1} x^n/n * Product_{k>=1} (1 + x^(n*k)) ).at n=22A218153
- Numbers n for which the digital sum contains the same distinct digits as the digital product but the digital sum is not equal to the digital product.at n=24A249335
- Number of integers in base n having exactly three distinct digits such that the number formed by the consecutive subsequence of the initial j digits is divisible by j for all j in {1,2,3}.at n=47A333405