Number of the day: 3504

Properties of the number 3504:

3504 = 2⁴ × 3 × 73 is the 3014^th composite number and is not squarefree.
3504 has 3 distinct prime factors, 20 divisors, 15 antidivisors and 1152 totatives.
3504 has an oblong digit sum 12 in base 10.
Reversing the decimal digits of 3504 results in a sphenic number.
3504 = 877² - 875² = 440² - 436² = 295² - 289² = 223² - 215² = 152² - 140² = 85² - 61² is the difference of 2 nonnegative squares in 6 ways.
3504 is the difference of 2 positive pentagonal numbers in 1 way.
3504 = 20² + 20² + 52² is the sum of 3 positive squares.
3504² = 2304² + 2640² is the sum of 2 positive squares in 1 way.
3504² is the sum of 3 positive squares.
3504 is a divisor of 439² - 1.
3504 is palindromic in (at least) the following bases: 28, and 72.
3504 in base 8 = 6660 and consists of only the digits '0' and '6'.
3504 in base 17 = c22 and consists of only the digits '2' and 'c'.
3504 in base 27 = 4ll and consists of only the digits '4' and 'l'.
3504 in base 28 = 4d4 and consists of only the digits '4' and 'd'.
3504 in base 29 = 44o and consists of only the digits '4' and 'o'.

The number 3504 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A001106: 9-gonal (or enneagonal or nonagonal) numbers: a(n) = n*(7*n-5)/2.
A033580: Four times second pentagonal numbers: a(n) = 2*n*(3*n+1).
A050208: Starting positions of strings of 2 1's in the decimal expansion of Pi.
A062717: Numbers m such that 6*m+1 is a perfect square.
A105078: Positive integers n such that n^10 + 1 is semiprime.
A183517: T(n,k)=Number of nXk binary arrays with each element equal to either the sum mod 2 of its horizontal and vertical neighbors or the sum mod 2 of its diagonal and antidiagonal neighbors
A199943: T(n,k)=Number of -k..k arrays x(0..n-1) of n elements with zeroth through n-1st differences all nonzero
A201155: T(n,k)=Number of nXk 0..2 arrays with every diagonal, row and column running average nondecreasing rightwards and downwards and diagonally
A207100: T(n,k)=Number of 0..k arrays x(0..n-1) of n elements with each no smaller than the sum of its two previous neighbors modulo (k+1)
A235954: T(n,k)=Number of (n+1)X(k+1) 0..2 arrays colored with the upper median value of each 2X2 subblock