1581328 has 30 divisors (see below), whose sum is σ = 3565806. Its totient is φ = 677376.

The previous prime is 1581317. The next prime is 1581367. The reversal of 1581328 is 8231851.

It can be written as a sum of positive squares in only one way, i.e., 1517824 + 63504 = 1232^2 + 252^2 .

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 1581296 and 1581305.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 225 + ... + 1792.

2^1581328 is an apocalyptic number.

It is an amenable number.

1581328 is an abundant number, since it is smaller than the sum of its proper divisors (1984478).

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

1581328 is a wasteful number, since it uses less digits than its factorization.

1581328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2039 (or 2026 counting only the distinct ones).

The product of its digits is 1920, while the sum is 28.

The square root of 1581328 is about 1257.5086480816. The cubic root of 1581328 is about 116.5039509427.

The spelling of 1581328 in words is "one million, five hundred eighty-one thousand, three hundred twenty-eight".