685438 has 16 divisors (see below), whose sum is σ = 1136016. Its totient is φ = 308160.

The previous prime is 685429. The next prime is 685453. The reversal of 685438 is 834586.

It is an Ulam number.

It is a congruent number.

It is an unprimeable number.

685438 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 745 + ... + 1387.

It is an arithmetic number, because the mean of its divisors is an integer number (71001).

2⁶⁸⁵⁴³⁸ is an apocalyptic number.

685438 is a deficient number, since it is larger than the sum of its proper divisors (450578).

685438 is a wasteful number, since it uses less digits than its factorization.

685438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 699.

The product of its digits is 23040, while the sum is 34.

The square root of 685438 is about 827.9118310545. The cubic root of 685438 is about 88.1703827076.

The spelling of 685438 in words is "six hundred eighty-five thousand, four hundred thirty-eight".