Number of the day: 3200

Properties of the number 3200:

3200 = 2⁷ × 5² is the 2747^th composite number and is not squarefree.
3200 has 2 distinct prime factors, 24 divisors, 12 antidivisors and 1280 totatives.
3200 has a prime digit sum 5 in base 10.
3200 has a Fibonacci digit sum 5 in base 10.
3200 is the difference of 2 nonnegative squares in 9 ways.
3200 is the difference of 2 positive pentagonal numbers in 1 way.
3200 = 40² + 40² = 8² + 56² is the sum of 2 positive squares in 2 ways.
3200 = 24² + 32² + 40² is the sum of 3 positive squares.
3200² = 1920² + 2560² = 896² + 3072² is the sum of 2 positive squares in 2 ways.
3200² is the sum of 3 positive squares.
3200 is a proper divisor of 449² - 1.
3200 is palindromic in (at least) the following bases: 7, 19, 39, 63, 79, 99, -21, and -41.
3200 in base 7 = 12221 and consists of only the digits '1' and '2'.
3200 in base 19 = 8g8 and consists of only the digits '8' and 'g'.
3200 in base 20 = 800 and consists of only the digits '0' and '8'.
3200 in base 38 = 288 and consists of only the digits '2' and '8'.
3200 in base 39 = 242 and consists of only the digits '2' and '4'.
3200 in base 40 = 200 and consists of only the digits '0' and '2'.
3200 in base 56 = 118 and consists of only the digits '1' and '8'.

The number 3200 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A001105: a(n) = 2*n^2.
A003592: Numbers of the form 2^i*5^j with i, j >= 0.
A032563: Numbers n such that A102489(n) is divisible by n.
A046312: Numbers that are divisible by exactly 9 primes with multiplicity.
A052486: Achilles numbers - powerful but imperfect: writing n=product(p_i^e_i) then none of the e_i=1 (i.e., powerful(1)) but the highest common factor of the e_i>1 is 1 (so not perfect powers).
A053191: a(n) = n^2 * phi(n).
A069540: Multiples of 5 with digit sum 5.
A077221: a(0) = 0 and then alternately even and odd numbers in increasing order such that the sum of any two successive terms is a square.
A121040: Multiples of 20 containing a 20 in their decimal representation.
A139098: a(n) = 8*n^2.