685584 has 75 divisors (see below), whose sum is σ = 2074303. Its totient is φ = 218592.

The previous prime is 685547. The next prime is 685591. The reversal of 685584 is 485586.

It is a happy number.

The square root of 685584 is 828.

It is a perfect power (a square), and thus also a powerful number.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a d-powerful number, because it can be written as 6 + 8⁵ + 5² + 5⁸ + 8⁶ + 4² .

It is a Duffinian number.

It is a nialpdrome in base 16.

It is an unprimeable number.

685584 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 29797 + ... + 29819.

2⁶⁸⁵⁵⁸⁴ is an apocalyptic number.

685584 is the 828-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 685584

685584 is an abundant number, since it is smaller than the sum of its proper divisors (1388719).

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

685584 is a wasteful number, since it uses less digits than its factorization.

685584 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66 (or 28 counting only the distinct ones).

The product of its digits is 38400, while the sum is 36.

The cubic root of 685584 is about 88.1766424335.

Multiplying 685584 by its sum of digits (36), we get a square (24681024 = 4968²).

685584 divided by its sum of digits (36) gives a square (19044 = 138²).

The spelling of 685584 in words is "six hundred eighty-five thousand, five hundred eighty-four".