685540 has 24 divisors (see below), whose sum is σ = 1455552. Its totient is φ = 271200.

The previous prime is 685537. The next prime is 685541. The reversal of 685540 is 45586.

It is a junction number, because it is equal to n+sod(n) for n = 685499 and 685508.

It is not an unprimeable number, because it can be changed into a prime (685541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2907 + ... + 3133.

It is an arithmetic number, because the mean of its divisors is an integer number (60648).

2⁶⁸⁵⁵⁴⁰ is an apocalyptic number.

It is an amenable number.

685540 is an abundant number, since it is smaller than the sum of its proper divisors (770012).

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

685540 is a wasteful number, since it uses less digits than its factorization.

685540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 387 (or 385 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 28.

The square root of 685540 is about 827.9734295254. The cubic root of 685540 is about 88.1747560343.

It can be divided in two parts, 685 and 540, that added together give a triangular number (1225 = T₄₉).

The spelling of 685540 in words is "six hundred eighty-five thousand, five hundred forty".