309128 has 16 divisors (see below), whose sum is σ = 613980. Its totient is φ = 145408.

The previous prime is 309121. The next prime is 309131. The reversal of 309128 is 821903.

It can be written as a sum of positive squares in 2 ways, for example, as 268324 + 40804 = 518^2 + 202^2 .

It is a nialpdrome in base 13.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 309128.

It is not an unprimeable number, because it can be changed into a prime (309121) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1001 + ... + 1272.

2³⁰⁹¹²⁸ is an apocalyptic number.

It is an amenable number.

309128 is a deficient number, since it is larger than the sum of its proper divisors (304852).

309128 is a wasteful number, since it uses less digits than its factorization.

309128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2296 (or 2292 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 309128 is about 555.9928057089. The cubic root of 309128 is about 67.6154767734.

The spelling of 309128 in words is "three hundred nine thousand, one hundred twenty-eight".