7931987985 has 16 divisors (see below), whose sum is σ = 12727763136. Its totient is φ = 4218199488.

The previous prime is 7931987981. The next prime is 7931988017. The reversal of 7931987985 is 5897891397.

It is not a de Polignac number, because 7931987985 - 2² = 7931987981 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (7931987981) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 756754 + ... + 767163.

It is an arithmetic number, because the mean of its divisors is an integer number (795485196).

Almost surely, 2^7931987985 is an apocalyptic number.

It is an amenable number.

7931987985 is a deficient number, since it is larger than the sum of its proper divisors (4795775151).

7931987985 is a wasteful number, since it uses less digits than its factorization.

7931987985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1524272.

The product of its digits is 34292160, while the sum is 66.

The square root of 7931987985 is about 89061.7088596441. The cubic root of 7931987985 is about 1994.3161945628.

The spelling of 7931987985 in words is "seven billion, nine hundred thirty-one million, nine hundred eighty-seven thousand, nine hundred eighty-five".