4015
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 10
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 5328
- Proper Divisor Sum (Aliquot Sum)
- 1313
- 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
- 2880
- Möbius Function
- -1
- Radical
- 4015
- 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
- 43
- 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
- Expansion of 1/((1+x)*(1-x)^5).at n=18A001752
- Number of permutations of (1,...,n) having n-5 inversions (n>=5).at n=6A005283
- a(n) = n*(n + 1)*(2*n^2 + 2*n - 1)/6.at n=9A006324
- Pseudoprimes to base 89.at n=42A020217
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly nine 1's.at n=8A020445
- a(n) = (d(n)-r(n))/2, where d = A026057 and r is the periodic sequence with fundamental period (0,0,1,0).at n=29A026058
- Number of distinct products ijk with 0 <= i < j < k <= n.at n=42A027429
- Numbers having period-1 5-digitized sequences.at n=42A031187
- Every run of digits of n in base 4 has length 2.at n=38A033002
- a(n) = (3*n+1)*(4*n+1).at n=18A033577
- Number of partitions of n into parts not of the form 15k, 15k+7 or 15k-7. Also number of partitions with at most 6 parts of size 1 and differences between parts at distance 6 are greater than 1.at n=31A035961
- Base-4 palindromes that start with 3.at n=40A043005
- Numbers whose base-4 representation contains exactly two 2's and four 3's.at n=9A045147
- Triangle read by rows: T(n,k) is the number of unlabeled nonseparable (or 2-connected) loopless multigraphs with n edges on k nodes and degree >= 3 at each node, n >= 3, 2 <= k <= floor(2*n/3).at n=50A046752
- Reduced sequence related to reciprocal Pythagorean triples: 1/a(n)^2 + 1/k^2 = 1/j^2 has an integer solution (k,j) with k<a(n) and a(n) not a multiple of 20.at n=42A065709
- a(n) is the smallest k such that (k^4 + 1)/(n^4 + 1) is an integer > 1.at n=37A066018
- CONTINUANT transform of A002487: 1, 1, 2, 1, 3, 2, ...at n=9A071898
- Numbers k such that 9^k + 8^(k-1) is prime.at n=6A093795
- Row sums of the triangle A097883.at n=19A098404
- Matrix inverse, read by rows, of triangle A104029, which forms the pairwise sums of trinomial coefficients.at n=16A104030