### Properties of the number 28920:

28920 = 2^{3}× 3 × 5 × 241 is the 25772

^{th}composite number and is not squarefree.

28920 has 4 distinct prime factors, 32 divisors, 9 antidivisors and 7680 totatives.

28920 has a semiprime digit sum 21 in base 10.

28920 has a Fibonacci digit sum 21 in base 10.

28920 has a triangular digit sum 21 in base 10.

28920 = (81 × 82)/2 + … + (88 × 89)/2 = (71 × 72)/2 + … + (80 × 81)/2 is the sum of at least 2 consecutive triangular numbers in 2 ways.

28920 = 7231

^{2}- 7229

^{2}= 3617

^{2}- 3613

^{2}= 2413

^{2}- 2407

^{2}= 1451

^{2}- 1441

^{2}= 1211

^{2}- 1199

^{2}= 733

^{2}- 713

^{2}= 497

^{2}- 467

^{2}= 271

^{2}- 211

^{2}is the difference of 2 nonnegative squares in 8 ways.

28920 = (240 × 241)/2 is a triangular number.

28920 is the difference of 2 positive pentagonal numbers in 2 ways.

28920 = 2

^{2}+ 4

^{2}+ 170

^{2}is the sum of 3 positive squares.

28920

^{2}= 14400

^{2}+ 25080

^{2}= 3528

^{2}+ 28704

^{2}= 11424

^{2}+ 26568

^{2}= 17352

^{2}+ 23136

^{2}is the sum of 2 positive squares in 4 ways.

28920

^{2}is the sum of 3 positive squares.

28920 is a divisor of 659

^{4}- 1.

28920 is palindromic in (at least) base 14.

28920 in base 14 = a77a and consists of only the digits '7' and 'a'.

28920 in base 15 = 8880 and consists of only the digits '0' and '8'.

28920 in base 19 = 4422 and consists of only the digits '2' and '4'.

28920 in base 42 = GGO and consists of only the digits 'G' and 'O'.

### The number 28920 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.A000385: Convolution of A000203 with itself.

A068131: Triangular numbers with sum of digits = 21.

A082036: (9*n^2+3*n+1)*n!.

A082038: A square array of quadratic-factorial numbers, read by antidiagonals.

A110450: a(n) = n*(n+1)*(n^2+n+1)/2.

A124494: Numbers n for which 2n-1, 4n-1, 8n-1 and 16n-1 are primes.

A222716: Numbers which are both the sum of n+1 consecutive triangular numbers and the sum of the n-1 immediately following triangular numbers.

A253651: Triangular numbers that are the product of a triangular number and a prime number.

A257712: Triangular numbers (A000217) that are the sum of eight consecutive triangular numbers.

A257713: Triangular numbers (A000217) that are the sum of ten consecutive triangular numbers.

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