391825728 has 224 divisors, whose sum is σ = 1363065600. Its totient is φ = 107993088.

The previous prime is 391825703. The next prime is 391825751. The reversal of 391825728 is 827528193.

It is a happy number.

391825728 is a `hidden beast` number, since 391 + 8 + 257 + 2 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (224).

It is a super-2 number, since 2×391825728² = 307054802245459968, which contains 22 as substring.

It is a congruent number.

It is an unprimeable 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 31 ways as a sum of consecutive naturals, for example, 350226 + ... + 351342.

Almost surely, 2^391825728 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 391825728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (681532800).

391825728 is an abundant number, since it is smaller than the sum of its proper divisors (971239872).

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

391825728 is a wasteful number, since it uses less digits than its factorization.

391825728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1174 (or 1158 counting only the distinct ones).

The product of its digits is 241920, while the sum is 45.

The square root of 391825728 is about 19794.5883513651. The cubic root of 391825728 is about 731.7526710775.

It can be divided in two parts, 3918 and 25728, that added together give a triangular number (29646 = T₂₄₃).

The spelling of 391825728 in words is "three hundred ninety-one million, eight hundred twenty-five thousand, seven hundred twenty-eight".