91000991091 has 8 divisors (see below), whose sum is σ = 121336311744. Its totient is φ = 60666498920.

The previous prime is 91000991077. The next prime is 91000991111. The reversal of 91000991091 is 19019900019.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 91000991091 - 2⁶ = 91000991027 is a prime.

It is a super-2 number, since 2×91000991091² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (91000991491) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 125476 + ... + 444686.

It is an arithmetic number, because the mean of its divisors is an integer number (15167038968).

Almost surely, 2^91000991091 is an apocalyptic number.

91000991091 is a deficient number, since it is larger than the sum of its proper divisors (30335320653).

91000991091 is a wasteful number, since it uses less digits than its factorization.

91000991091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 414241.

The product of its (nonzero) digits is 6561, while the sum is 39.

The spelling of 91000991091 in words is "ninety-one billion, nine hundred ninety-one thousand, ninety-one".