91090991091 has 16 divisors (see below), whose sum is σ = 127856016000. Its totient is φ = 57527097408.

The previous prime is 91090991059. The next prime is 91090991093. The reversal of 91090991091 is 19019909019.

It is not a de Polignac number, because 91090991091 - 2⁵ = 91090991059 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 91090991091.

It is not an unprimeable number, because it can be changed into a prime (91090991093) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 901000 + ... + 996986.

It is an arithmetic number, because the mean of its divisors is an integer number (7991001000).

Almost surely, 2^91090991091 is an apocalyptic number.

91090991091 is a deficient number, since it is larger than the sum of its proper divisors (36765024909).

91090991091 is a wasteful number, since it uses less digits than its factorization.

91090991091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112658.

The product of its (nonzero) digits is 59049, while the sum is 48.

The spelling of 91090991091 in words is "ninety-one billion, ninety million, nine hundred ninety-one thousand, ninety-one".