Number of the day: 28203

Properties of the number 28203:

28203 = 3 × 7 × 17 × 79 is the 25128^th composite number and is squarefree.
28203 has 4 distinct prime factors, 16 divisors, 23 antidivisors and 14976 totatives.
28203 has an emirpimes digit sum 15 in base 10.
28203 has a triangular digit sum 15 in base 10.
28203 = 14102² - 14101² = 4702² - 4699² = 2018² - 2011² = 838² - 821² = 682² - 661² = 302² - 251² = 218² - 139² = 178² - 59² is the difference of 2 nonnegative squares in 8 ways.
28203 = (237 × 238)/2 is a triangular number.
28203 is the difference of 2 positive pentagonal numbers in 3 ways.
28203 = 5² + 17² + 167² is the sum of 3 positive squares.
28203² = 13272² + 24885² is the sum of 2 positive squares in 1 way.
28203² is the sum of 3 positive squares.
28203 is a proper divisor of 103⁶ - 1.
28203 is palindromic in (at least) the following bases: 20, 94, and -100.
28203 in base 20 = 3aa3 and consists of only the digits '3' and 'a'.

The number 28203 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A068130: Triangular numbers with sum of digits = 15.
A069702: Triangular numbers with internal digits also forming a triangular number.
A117062: Hexagonal numbers for which the sum of the digits is also a hexagonal number.
A117345: Indices n such that the 3 X 3 matrix with components (row by row) prime(n+k), 0 <= k <= 8, has zero determinant.
A145678: a(n) = 441*n^2 - 21.
A157948: a(n) = 64*n^2 - n.
A212240: Number of 2 X 2 matrices M of with all terms in {1,...,n} and permanent(M) >= n.
A247016: Triangular numbers A000217 composed of only curved digits {0, 2, 3, 5, 6, 8, 9}.
A302428: Number of 3Xn 0..1 arrays with every element equal to 0, 1, 3 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.
A333771: Triangular numbers that are the product of four distinct primes.