1581947640025 has 27 divisors (see below), whose sum is σ = 2050798352701. Its totient is φ = 1210423163840.

The previous prime is 1581947640019. The next prime is 1581947640037. The reversal of 1581947640025 is 5200467491851.

The square root of 1581947640025 is 1257755.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 278212996681 + 1303734643344 = 527459^2 + 1141812^2 .

It is not a de Polignac number, because 1581947640025 - 2³³ = 1573357705433 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 144636357 + ... + 144647293.

Almost surely, 2^{1581947640025} is an apocalyptic number.

1581947640025 is the 1257755-th square number.

1581947640025 is the 628878-th centered octagonal number.

It is an amenable number.

1581947640025 is a deficient number, since it is larger than the sum of its proper divisors (468850712676).

1581947640025 is an frugal number, since it uses more digits than its factorization.

1581947640025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21930 (or 10965 counting only the distinct ones).

The product of its (nonzero) digits is 2419200, while the sum is 52.

The spelling of 1581947640025 in words is "one trillion, five hundred eighty-one billion, nine hundred forty-seven million, six hundred forty thousand, twenty-five".