91811391612 has 12 divisors (see below), whose sum is σ = 214226580456. Its totient is φ = 30603797200.

The previous prime is 91811391599. The next prime is 91811391619. The reversal of 91811391612 is 21619311819.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91811391619) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3825474639 + ... + 3825474662.

It is an arithmetic number, because the mean of its divisors is an integer number (17852215038).

Almost surely, 2^91811391612 is an apocalyptic number.

It is an amenable number.

91811391612 is an abundant number, since it is smaller than the sum of its proper divisors (122415188844).

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

91811391612 is a wasteful number, since it uses less digits than its factorization.

91811391612 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7650949308 (or 7650949306 counting only the distinct ones).

The product of its digits is 23328, while the sum is 42.

The spelling of 91811391612 in words is "ninety-one billion, eight hundred eleven million, three hundred ninety-one thousand, six hundred twelve".