685438566 has 16 divisors (see below), whose sum is σ = 1443028800. Its totient is φ = 216454248.

The previous prime is 685438561. The next prime is 685438597. The reversal of 685438566 is 665834586.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685438561) 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 7 ways as a sum of consecutive naturals, for example, 3006196 + ... + 3006423.

It is an arithmetic number, because the mean of its divisors is an integer number (90189300).

Almost surely, 2^685438566 is an apocalyptic number.

685438566 is an abundant number, since it is smaller than the sum of its proper divisors (757590234).

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

685438566 is a wasteful number, since it uses less digits than its factorization.

685438566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6012643.

The product of its digits is 4147200, while the sum is 51.

The square root of 685438566 is about 26180.8816887438. The cubic root of 685438566 is about 881.7040697648.

The spelling of 685438566 in words is "six hundred eighty-five million, four hundred thirty-eight thousand, five hundred sixty-six".