391028 has 12 divisors (see below), whose sum is σ = 746592. Its totient is φ = 177720.

The previous prime is 391021. The next prime is 391031. The reversal of 391028 is 820193.

It is a junction number, because it is equal to n+sod(n) for n = 390994 and 391012.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 391028.

It is not an unprimeable number, because it can be changed into a prime (391021) by changing a digit.

391028 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 3 ways as a sum of consecutive naturals, for example, 4400 + ... + 4487.

It is an arithmetic number, because the mean of its divisors is an integer number (62216).

2³⁹¹⁰²⁸ is an apocalyptic number.

It is an amenable number.

391028 is a deficient number, since it is larger than the sum of its proper divisors (355564).

391028 is a wasteful number, since it uses less digits than its factorization.

391028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8902 (or 8900 counting only the distinct ones).

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

The square root of 391028 is about 625.3223168895. The cubic root of 391028 is about 73.1255735704.

The spelling of 391028 in words is "three hundred ninety-one thousand, twenty-eight".