685508840 has 32 divisors (see below), whose sum is σ = 1548153000. Its totient is φ = 273179904.

The previous prime is 685508839. The next prime is 685508849. The reversal of 685508840 is 48805586.

It can be written as a sum of positive squares in 4 ways, for example, as 218862436 + 466646404 = 14794^2 + 21602^2 .

It is a junction number, because it is equal to n+sod(n) for n = 685508791 and 685508800.

It is not an unprimeable number, because it can be changed into a prime (685508849) 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, 21095 + ... + 42614.

Almost surely, 2^685508840 is an apocalyptic number.

It is an amenable number.

685508840 is an abundant number, since it is smaller than the sum of its proper divisors (862644160).

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

685508840 is a wasteful number, since it uses less digits than its factorization.

685508840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63989 (or 63985 counting only the distinct ones).

The product of its (nonzero) digits is 307200, while the sum is 44.

The square root of 685508840 is about 26182.2237405458. The cubic root of 685508840 is about 881.7342007192.

The spelling of 685508840 in words is "six hundred eighty-five million, five hundred eight thousand, eight hundred forty".