685990 has 16 divisors (see below), whose sum is σ = 1244880. Its totient is φ = 272160.

The previous prime is 685987. The next prime is 685991. The reversal of 685990 is 99586.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685991) 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, 1621 + ... + 1999.

It is an arithmetic number, because the mean of its divisors is an integer number (77805).

2⁶⁸⁵⁹⁹⁰ is an apocalyptic number.

685990 is a deficient number, since it is larger than the sum of its proper divisors (558890).

685990 is a wasteful number, since it uses less digits than its factorization.

685990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 567.

The product of its (nonzero) digits is 19440, while the sum is 37.

The square root of 685990 is about 828.2451327958. The cubic root of 685990 is about 88.1940449460.

The spelling of 685990 in words is "six hundred eighty-five thousand, nine hundred ninety".