1640585728 has 40 divisors (see below), whose sum is σ = 3331767780. Its totient is φ = 806830080.

The previous prime is 1640585717. The next prime is 1640585741. The reversal of 1640585728 is 8275850461.

It can be written as a sum of positive squares in 2 ways, for example, as 1100116224 + 540469504 = 33168^2 + 23248^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4968 + ... + 57496.

Almost surely, 2^1640585728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1640585728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1665883890).

1640585728 is an abundant number, since it is smaller than the sum of its proper divisors (1691182052).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1640585728 is an frugal number, since it uses more digits than its factorization.

1640585728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52608 (or 52592 counting only the distinct ones).

The product of its (nonzero) digits is 537600, while the sum is 46.

The square root of 1640585728 is about 40504.1445780552. The cubic root of 1640585728 is about 1179.4140842979.

The spelling of 1640585728 in words is "one billion, six hundred forty million, five hundred eighty-five thousand, seven hundred twenty-eight".