Sunday, February 18, 2018

Number of the day: 28180

Properties of the number 28180:

28180 = 22 × 5 × 1409 is the 25108th composite number and is not squarefree.
28180 has 3 distinct prime factors, 12 divisors, 5 antidivisors and 11264 totatives.
28180 has a prime digit sum 19 in base 10.
28180 = 70462 - 70442 = 14142 - 14042 is the difference of 2 nonnegative squares in 2 ways.
28180 is the difference of 2 positive pentagonal numbers in 2 ways.
28180 = 622 + 1562 = 442 + 1622 is the sum of 2 positive squares in 2 ways.
28180 = 602 + 622 + 1442 is the sum of 3 positive squares.
281802 = 142562 + 243082 = 31802 + 280002 = 193442 + 204922 = 169082 + 225442 is the sum of 2 positive squares in 4 ways.
281802 is the sum of 3 positive squares.
28180 is a proper divisor of 18614 - 1.
28180 is palindromic in (at least) base 43.
28180 in base 38 = JJM and consists of only the digits 'J' and 'M'.
28180 in base 42 = Fee and consists of only the digits 'F' and 'e'.
28180 in base 43 = FAF and consists of only the digits 'A' and 'F'.

The number 28180 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequence (among others):

Sequence number and description below are taken from OEIS.
A293597: L.g.f.: Sum_{n>=1} (x - x^(2*n-1))^(2*n-1) / (2*n-1).

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