1991528 has 64 divisors (see below), whose sum is σ = 4821120. Its totient is φ = 748800.

The previous prime is 1991527. The next prime is 1991551. The reversal of 1991528 is 8251991.

It is not an unprimeable number, because it can be changed into a prime (1991527) 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, 32618 + ... + 32678.

It is an arithmetic number, because the mean of its divisors is an integer number (75330).

2^1991528 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 1991528, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2410560).

1991528 is an abundant number, since it is smaller than the sum of its proper divisors (2829592).

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

1991528 is a wasteful number, since it uses less digits than its factorization.

1991528 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138 (or 134 counting only the distinct ones).

The product of its digits is 6480, while the sum is 35.

The square root of 1991528 is about 1411.2150792845. The cubic root of 1991528 is about 125.8139523484.

The spelling of 1991528 in words is "one million, nine hundred ninety-one thousand, five hundred twenty-eight".