99181531691 has 4 divisors (see below), whose sum is σ = 108198034584. Its totient is φ = 90165028800.

The previous prime is 99181531619. The next prime is 99181531717. The reversal of 99181531691 is 19613518199.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 99181531691 - 2³⁰ = 98107789867 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (99181531601) 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 3 ways as a sum of consecutive naturals, for example, 4508251430 + ... + 4508251451.

It is an arithmetic number, because the mean of its divisors is an integer number (27049508646).

Almost surely, 2^99181531691 is an apocalyptic number.

99181531691 is a deficient number, since it is larger than the sum of its proper divisors (9016502893).

99181531691 is a wasteful number, since it uses less digits than its factorization.

99181531691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9016502892.

The product of its digits is 524880, while the sum is 53.

The spelling of 99181531691 in words is "ninety-nine billion, one hundred eighty-one million, five hundred thirty-one thousand, six hundred ninety-one".