391552728 has 96 divisors (see below), whose sum is σ = 1154550960. Its totient is φ = 110315520.

The previous prime is 391552691. The next prime is 391552739. The reversal of 391552728 is 827255193.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a self number, because there is not a number n which added to its sum of digits gives 391552728.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 83568 + ... + 88128.

Almost surely, 2^391552728 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 391552728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (577275480).

391552728 is an abundant number, since it is smaller than the sum of its proper divisors (762998232).

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

391552728 is a wasteful number, since it uses less digits than its factorization.

391552728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4657 (or 4646 counting only the distinct ones).

The product of its digits is 151200, while the sum is 42.

The square root of 391552728 is about 19787.6913256701. The cubic root of 391552728 is about 731.5826848835.

The spelling of 391552728 in words is "three hundred ninety-one million, five hundred fifty-two thousand, seven hundred twenty-eight".