91131687198 has 40 divisors (see below), whose sum is σ = 209183047920. Its totient is φ = 29636318880.

The previous prime is 91131687173. The next prime is 91131687263. The reversal of 91131687198 is 89178613119.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 6853618 + ... + 6866901.

It is an arithmetic number, because the mean of its divisors is an integer number (5229576198).

Almost surely, 2^91131687198 is an apocalyptic number.

91131687198 is an abundant number, since it is smaller than the sum of its proper divisors (118051360722).

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

91131687198 is a wasteful number, since it uses less digits than its factorization.

91131687198 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13720574 (or 13720565 counting only the distinct ones).

The product of its digits is 653184, while the sum is 54.

The spelling of 91131687198 in words is "ninety-one billion, one hundred thirty-one million, six hundred eighty-seven thousand, one hundred ninety-eight".