309961728 has 220 divisors, whose sum is σ = 960034812. Its totient is φ = 99532800.

The previous prime is 309961727. The next prime is 309961783. The reversal of 309961728 is 827169903.

309961728 is a `hidden beast` number, since 3 + 0 + 9 + 9 + 617 + 28 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 288728064 + 21233664 = 16992^2 + 4608^2 .

It is not an unprimeable number, because it can be changed into a prime (309961727) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 3068878 + ... + 3068978.

Almost surely, 2^309961728 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 309961728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (480017406).

309961728 is an abundant number, since it is smaller than the sum of its proper divisors (650073084).

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

309961728 is a wasteful number, since it uses less digits than its factorization.

309961728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 170 (or 143 counting only the distinct ones).

The product of its (nonzero) digits is 163296, while the sum is 45.

The square root of 309961728 is about 17605.7299763458. The cubic root of 309961728 is about 676.7620923389.

The spelling of 309961728 in words is "three hundred nine million, nine hundred sixty-one thousand, seven hundred twenty-eight".