685784638 has 16 divisors (see below), whose sum is σ = 1282506624. Its totient is φ = 267188760.

The previous prime is 685784623. The next prime is 685784639. The reversal of 685784638 is 836487586.

685784638 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685784639) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2226420 + ... + 2226727.

It is an arithmetic number, because the mean of its divisors is an integer number (80156664).

Almost surely, 2^685784638 is an apocalyptic number.

685784638 is a deficient number, since it is larger than the sum of its proper divisors (596721986).

685784638 is a wasteful number, since it uses less digits than its factorization.

685784638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4453167.

The product of its digits is 7741440, while the sum is 55.

The square root of 685784638 is about 26187.4901050101. The cubic root of 685784638 is about 881.8524330500.

It can be divided in two parts, 6 and 85784638, that added together give a square (85784644 = 9262²).

The spelling of 685784638 in words is "six hundred eighty-five million, seven hundred eighty-four thousand, six hundred thirty-eight".