7991111997 has 32 divisors (see below), whose sum is σ = 12965304960. Its totient is φ = 4824207360.

The previous prime is 7991111993. The next prime is 7991112007.

7991111997 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 7991111997 - 2² = 7991111993 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7991111993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 23983 + ... + 128675.

It is an arithmetic number, because the mean of its divisors is an integer number (405165780).

Almost surely, 2^7991111997 is an apocalyptic number.

It is an amenable number.

7991111997 is a deficient number, since it is larger than the sum of its proper divisors (4974192963).

7991111997 is a wasteful number, since it uses less digits than its factorization.

7991111997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104970 (or 104964 counting only the distinct ones).

The product of its digits is 321489, while the sum is 54.

The square root of 7991111997 is about 89393.0198449521. The cubic root of 7991111997 is about 1999.2590586202.

It can be divided in two parts, 799111 and 1997, that added together give a palindrome (801108).

The spelling of 7991111997 in words is "seven billion, nine hundred ninety-one million, one hundred eleven thousand, nine hundred ninety-seven".