15180
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 48
- Divisor Sum
- 48384
- Proper Divisor Sum (Aliquot Sum)
- 33204
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 3520
- Möbius Function
- 0
- Radical
- 7590
- Omega Function (Ω)
- 6
- Little Omega Function (ω)
- 5
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
- yes
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- no
Recreational
- Happy Number
- yes
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 71
- 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
- Tetrahedral (or triangular pyramidal) numbers: a(n) = C(n+2,3) = n*(n+1)*(n+2)/6.at n=44A000292
- Number of compositions of n into 4 ordered relatively prime parts.at n=43A000742
- Sum of the first n even squares: a(n) = 2*n*(n+1)*(2*n+1)/3.at n=22A002492
- Expansion of hypergeom([3/2, 7/4, 2, 9/4], [7/3, 8/3, 3], (256/27)*x).at n=5A006633
- Binomial coefficient C(46,n).at n=3A010962
- Binomial coefficient C(n,43).at n=3A010996
- Floor[n(n-1)(n-2)(n-3)/14].at n=23A011924
- a(n) = floor(n(n-1)(n-2)(n-3)/20).at n=25A011930
- Even tetrahedral numbers.at n=33A015220
- a(n) = n*(19*n - 1)/2.at n=40A022276
- s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (odd natural numbers), t = A001950 (upper Wythoff sequence).at n=31A025114
- (prime(n)-5)(prime(n)-7)(prime(n)-9)/48.at n=22A030002
- Number of nonempty subsets of {1,2,...,n} in which exactly 3/4 of the elements are <= n/3.at n=26A047197
- Number of nonempty subsets of {1,2,...,n} in which exactly 3/4 of the elements are <= (n+1)/3.at n=26A048042
- Number of nonempty subsets of {1,2,...,n} in which exactly 3/4 of the elements are <= (n+2)/3.at n=26A048075
- Denominators of row 4 of table described in A051714/A051715.at n=18A051723
- Numbers k such that the sign of core(k)-phi(k) is not equal to 2*mu(k)^2-1, where core(k) is the squarefree part of k.at n=23A070237
- Product of prime divisors of composite numbers between consecutive primes.at n=13A074167
- Non-palindromic n and its digit reversal have the same sum of prime factors (with repetition).at n=36A085607
- Number of subsets S of {1,2,...,n} which contain a number that is greater than the sum of the other numbers in S.at n=31A095944