665008857 has 12 divisors (see below), whose sum is σ = 961614420. Its totient is φ = 442856448.

The previous prime is 665008849. The next prime is 665008859. The reversal of 665008857 is 758800566.

665008857 is a `hidden beast` number, since 66 + 500 + 8 + 85 + 7 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 322166601 + 342842256 = 17949^2 + 18516^2 .

It is not a de Polignac number, because 665008857 - 2³ = 665008849 is a prime.

It is not an unprimeable number, because it can be changed into a prime (665008859) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 31408 + ... + 48129.

It is an arithmetic number, because the mean of its divisors is an integer number (80134535).

Almost surely, 2^665008857 is an apocalyptic number.

It is an amenable number.

665008857 is a deficient number, since it is larger than the sum of its proper divisors (296605563).

665008857 is a wasteful number, since it uses less digits than its factorization.

665008857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80472 (or 80469 counting only the distinct ones).

The product of its (nonzero) digits is 403200, while the sum is 45.

The square root of 665008857 is about 25787.7656457476. The cubic root of 665008857 is about 872.8557486137.

It can be divided in two parts, 66500 and 8857, that added together give a palindrome (75357).

The spelling of 665008857 in words is "six hundred sixty-five million, eight thousand, eight hundred fifty-seven".