309680728 has 32 divisors (see below), whose sum is σ = 664220160. Its totient is φ = 132596640.

The previous prime is 309680699. The next prime is 309680729. The reversal of 309680728 is 827086903.

309680728 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (309680729) 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, 83473 + ... + 87103.

It is an arithmetic number, because the mean of its divisors is an integer number (20756880).

Almost surely, 2^309680728 is an apocalyptic number.

It is an amenable number.

309680728 is an abundant number, since it is smaller than the sum of its proper divisors (354539432).

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

309680728 is a wasteful number, since it uses less digits than its factorization.

309680728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5167 (or 5163 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 43.

The square root of 309680728 is about 17597.7478104444. The cubic root of 309680728 is about 676.5575212291.

The spelling of 309680728 in words is "three hundred nine million, six hundred eighty thousand, seven hundred twenty-eight".