91111020191 has 32 divisors (see below), whose sum is σ = 94996108800. Its totient is φ = 87342368256.

The previous prime is 91111020181. The next prime is 91111020223. The reversal of 91111020191 is 19102011119.

It is a cyclic number.

It is not a de Polignac number, because 91111020191 - 2¹⁴ = 91111003807 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 91111020191.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91111020181) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 152104910 + ... + 152105508.

It is an arithmetic number, because the mean of its divisors is an integer number (2968628400).

Almost surely, 2^91111020191 is an apocalyptic number.

91111020191 is a deficient number, since it is larger than the sum of its proper divisors (3885088609).

91111020191 is a wasteful number, since it uses less digits than its factorization.

91111020191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1103.

The product of its (nonzero) digits is 162, while the sum is 26.

The spelling of 91111020191 in words is "ninety-one billion, one hundred eleven million, twenty thousand, one hundred ninety-one".