3991328 has 96 divisors (see below), whose sum is σ = 9797760. Its totient is φ = 1576960.

The previous prime is 3991321. The next prime is 3991331. The reversal of 3991328 is 8231993.

3991328 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a nialpdrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (3991321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 137618 + ... + 137646.

It is an arithmetic number, because the mean of its divisors is an integer number (102060).

Almost surely, 2^3991328 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 3991328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4898880).

3991328 is an abundant number, since it is smaller than the sum of its proper divisors (5806432).

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

3991328 is a wasteful number, since it uses less digits than its factorization.

3991328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90 (or 82 counting only the distinct ones).

The product of its digits is 11664, while the sum is 35.

The square root of 3991328 is about 1997.8308236685. The cubic root of 3991328 is about 158.6253060126.

The spelling of 3991328 in words is "three million, nine hundred ninety-one thousand, three hundred twenty-eight".