1581565972 has 48 divisors (see below), whose sum is σ = 3243461760. Its totient is φ = 660667392.

The previous prime is 1581565957. The next prime is 1581565991. The reversal of 1581565972 is 2795651851.

Its product of digits (756000) is a multiple of the sum of its prime factors (2800).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 741804 + ... + 743932.

It is an arithmetic number, because the mean of its divisors is an integer number (67572120).

Almost surely, 2^1581565972 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 1581565972, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1621730880).

1581565972 is an abundant number, since it is smaller than the sum of its proper divisors (1661895788).

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

1581565972 is a wasteful number, since it uses less digits than its factorization.

1581565972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2800 (or 2798 counting only the distinct ones).

The product of its digits is 756000, while the sum is 49.

The square root of 1581565972 is about 39768.9071008998. The cubic root of 1581565972 is about 1165.0979482568.

The spelling of 1581565972 in words is "one billion, five hundred eighty-one million, five hundred sixty-five thousand, nine hundred seventy-two".