665587728 has 60 divisors (see below), whose sum is σ = 2006013100. Its totient is φ = 204795648.

The previous prime is 665587721. The next prime is 665587733. The reversal of 665587728 is 827785566.

665587728 is a `hidden beast` number, since 66 + 558 + 7 + 7 + 28 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 217503504 + 448084224 = 14748^2 + 21168^2 .

It is not an unprimeable number, because it can be changed into a prime (665587721) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 175903 + ... + 179646.

Almost surely, 2^665587728 is an apocalyptic number.

It is an amenable number.

665587728 is an abundant number, since it is smaller than the sum of its proper divisors (1340425372).

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

665587728 is a wasteful number, since it uses less digits than its factorization.

665587728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 355576 (or 355567 counting only the distinct ones).

The product of its digits is 5644800, while the sum is 54.

The square root of 665587728 is about 25798.9869568555. The cubic root of 665587728 is about 873.1089404009.

The spelling of 665587728 in words is "six hundred sixty-five million, five hundred eighty-seven thousand, seven hundred twenty-eight".