309728805 has 16 divisors (see below), whose sum is σ = 495890880. Its totient is φ = 165080448.

The previous prime is 309728803. The next prime is 309728863. The reversal of 309728805 is 508827903.

It is not a de Polignac number, because 309728805 - 2¹ = 309728803 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (309728803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20406 + ... + 32184.

It is an arithmetic number, because the mean of its divisors is an integer number (30993180).

Almost surely, 2^309728805 is an apocalyptic number.

It is an amenable number.

309728805 is a deficient number, since it is larger than the sum of its proper divisors (186162075).

309728805 is a wasteful number, since it uses less digits than its factorization.

309728805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13540.

The product of its (nonzero) digits is 120960, while the sum is 42.

The square root of 309728805 is about 17599.1137560958. The cubic root of 309728805 is about 676.5925305898.

The spelling of 309728805 in words is "three hundred nine million, seven hundred twenty-eight thousand, eight hundred five".