5640
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 32
- Divisor Sum
- 17280
- Proper Divisor Sum (Aliquot Sum)
- 11640
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 1472
- Möbius Function
- 0
- Radical
- 1410
- Omega Function (Ω)
- 6
- 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
- 36
- 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
- 5 times triangular numbers: a(n) = 5*n*(n+1)/2.at n=47A028895
- Least term in period of continued fraction for sqrt(n) is 10.at n=15A031434
- Decimal part of cube root of a(n) starts with 8: first term of runs.at n=16A034134
- Multiplicity of highest weight (or singular) vectors associated with character chi_141 of Monster module.at n=38A034529
- Numbers for which reduced residue system contains as many primes as nonprimes.at n=27A048869
- a(n) = Sum_{i=0..n} T(i,n-i) where T is A049627.at n=37A049628
- Consider the Diophantine equation x^3 + y^3 = z^3 + 1 (1 < x < y < z) or 'Fermat near misses'. Sequence gives values of z in monotonic increasing order.at n=12A050791
- Lesser members of g-reduced amicable pairs a < b such that sigma(a) = sigma(b) = a + b + gcd(a,b).at n=30A054573
- Numbers k such that 5*2^k - 3 is prime.at n=40A058588
- Numbers k such that phi(x) = k has exactly 11 solutions.at n=17A060674
- If n-th triangular number (A000217(n)) is odd, multiply it by 4; if even, multiply it by 5.at n=46A061726
- Stirling transform of squares of Bell numbers: a(0)=1, a(n) = Sum_{k=1..n} Stirling2(n,k)*(bell(k))^2.at n=5A069471
- At these values of k the first, 2nd and 3rd cyclotomic polynomials all give prime numbers.at n=25A070020
- a(n) = Sum_{k=1..n} antisigma(k), where antisigma(i) = sum of the nondivisors of i that are between 1 and i.at n=32A076664
- Non-balanced numbers in A015769.at n=43A077803
- Row sums in A083175.at n=14A083175
- Numbers that can be expressed as the difference of the squares of primes in just three distinct ways.at n=20A090782
- Expansion of eta(q^6) * eta(q^10) / (eta(q) * eta(q^15)) in powers of q.at n=33A094023
- Numbers k with property that k is a peak value in 3x+1 trajectory such that both k+1 and k-1 are prime numbers.at n=27A095385
- Numbers n for which there are exactly five k such that n = k + (product of nonzero digits of k).at n=15A096926