Number of the day: 27930

Luitzen Egbertus Jan Brouwer was born on this day 137 years ago.

Properties of the number 27930:

27930 = 2 × 3 × 5 × 7² × 19 is the 24882^th composite number and is not squarefree.
27930 has 5 distinct prime factors, 48 divisors, 27 antidivisors and 6048 totatives.
27930 has a semiprime digit sum 21 in base 10.
27930 has a Fibonacci digit sum 21 in base 10.
27930 has a triangular digit sum 21 in base 10.
27930 = (20 × 21)/2 + … + (55 × 56)/2 is the sum of at least 2 consecutive triangular numbers in 1 way.
27930 is the sum of 2 positive triangular numbers.
27930 is the difference of 2 positive pentagonal numbers in 5 ways.
27930 = 4² + 5² + 167² is the sum of 3 positive squares.
27930² = 16758² + 22344² is the sum of 2 positive squares in 1 way.
27930² is the sum of 3 positive squares.
27930 is a proper divisor of 1861² - 1.
27930 is palindromic in (at least) the following bases: 11, 47, 87, and -31.
27930 in base 30 = 1110 and consists of only the digits '0' and '1'.
27930 in base 47 = CUC and consists of only the digits 'C' and 'U'.

The number 27930 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A002624: Expansion of (1-x)^(-3) * (1-x^2)^(-2).
A004320: a(n) = n*(n+1)*(n+2)^2/6.
A027444: a(n) = n^3 + n^2 + n.
A069070: Numbers n such that n*sigma(n) is a perfect square.
A091054: Expansion of (1-5x+2x^2)/((1-x)(1+2x)(1-6x)).
A132461: Row squared sums of triangle of Lucas polynomials (A034807) for n>0: Sum_{k=0..floor(n/2)} A034807(n,k)^2, with a(0)=1.
A189507: Triangle read by rows: T(n,k) (n >= 0, 1 <= k <= n+1) are the signed Hultman numbers.
A203108: T(n,k)=Number of nXk binary arrays with every 1 immediately preceded by 0 0 to the left or above
A241649: Numbers m such that the GCD of the x's that satisfy sigma(x)=m is 4.
A255048: Partial sums of A253088.