309828 has 12 divisors (see below), whose sum is σ = 722960. Its totient is φ = 103272.

The previous prime is 309823. The next prime is 309851. The reversal of 309828 is 828903.

It is a tau number, because it is divible by the number of its divisors (12).

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 309795 and 309804.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 309828.

It is not an unprimeable number, because it can be changed into a prime (309823) 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, 12898 + ... + 12921.

2³⁰⁹⁸²⁸ is an apocalyptic number.

It is an amenable number.

309828 is an abundant number, since it is smaller than the sum of its proper divisors (413132).

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

309828 is a wasteful number, since it uses less digits than its factorization.

309828 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25826 (or 25824 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 309828 is about 556.6219542921. The cubic root of 309828 is about 67.6664752301. Note that the first 3 decimals are identical.

The spelling of 309828 in words is "three hundred nine thousand, eight hundred twenty-eight".