664666857 has 16 divisors (see below), whose sum is σ = 1027505280. Its totient is φ = 423845136.

The previous prime is 664666843. The next prime is 664666859. The reversal of 664666857 is 758666466.

664666857 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 664666857 - 2¹¹ = 664664809 is a prime.

It is not an unprimeable number, because it can be changed into a prime (664666859) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 534538 + ... + 535779.

It is an arithmetic number, because the mean of its divisors is an integer number (64219080).

Almost surely, 2^664666857 is an apocalyptic number.

It is an amenable number.

664666857 is a deficient number, since it is larger than the sum of its proper divisors (362838423).

664666857 is a wasteful number, since it uses less digits than its factorization.

664666857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1070349 (or 1070343 counting only the distinct ones).

The product of its digits is 8709120, while the sum is 54.

The square root of 664666857 is about 25781.1337415561. The cubic root of 664666857 is about 872.7060925346.

The spelling of 664666857 in words is "six hundred sixty-four million, six hundred sixty-six thousand, eight hundred fifty-seven".