685998 has 24 divisors (see below), whose sum is σ = 1551888. Its totient is φ = 218592.

The previous prime is 685991. The next prime is 686003. The reversal of 685998 is 899586.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 685998.

It is not an unprimeable number, because it can be changed into a prime (685991) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 415 + ... + 1242.

It is an arithmetic number, because the mean of its divisors is an integer number (64662).

2⁶⁸⁵⁹⁹⁸ is an apocalyptic number.

685998 is an abundant number, since it is smaller than the sum of its proper divisors (865890).

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

685998 is a wasteful number, since it uses less digits than its factorization.

685998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1688 (or 1685 counting only the distinct ones).

The product of its digits is 155520, while the sum is 45.

The square root of 685998 is about 828.2499622698. The cubic root of 685998 is about 88.1943877836.

The spelling of 685998 in words is "six hundred eighty-five thousand, nine hundred ninety-eight".