685639680 has 192 divisors, whose sum is σ = 2394100800. Its totient is φ = 166133760.

The previous prime is 685639651. The next prime is 685639693. The reversal of 685639680 is 86936586.

It is a tau number, because it is divible by the number of its divisors (192).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 336906 + ... + 338934.

It is an arithmetic number, because the mean of its divisors is an integer number (12469275).

Almost surely, 2^685639680 is an apocalyptic number.

685639680 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 685639680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1197050400).

685639680 is an abundant number, since it is smaller than the sum of its proper divisors (1708461120).

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

685639680 is a wasteful number, since it uses less digits than its factorization.

685639680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2070 (or 2050 counting only the distinct ones).

The product of its (nonzero) digits is 1866240, while the sum is 51.

The square root of 685639680 is about 26184.7222631824. The cubic root of 685639680 is about 881.7902947023.

The spelling of 685639680 in words is "six hundred eighty-five million, six hundred thirty-nine thousand, six hundred eighty".