686624320 has 56 divisors (see below), whose sum is σ = 1653463800. Its totient is φ = 271552512.

The previous prime is 686624303. The next prime is 686624321. The reversal of 686624320 is 23426686.

It can be written as a sum of positive squares in 4 ways, for example, as 32901696 + 653722624 = 5736^2 + 25568^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 686624320.

It is not an unprimeable number, because it can be changed into a prime (686624321) 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, 16426 + ... + 40534.

Almost surely, 2^686624320 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 686624320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (826731900).

686624320 is an abundant number, since it is smaller than the sum of its proper divisors (966839480).

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

686624320 is a wasteful number, since it uses less digits than its factorization.

686624320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24215 (or 24205 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 37.

The square root of 686624320 is about 26203.5173211537. The cubic root of 686624320 is about 882.2122027520.

The spelling of 686624320 in words is "six hundred eighty-six million, six hundred twenty-four thousand, three hundred twenty".