91000091001 has 4 divisors (see below), whose sum is σ = 121333454672. Its totient is φ = 60666727332.

The previous prime is 91000090981. The next prime is 91000091023. The reversal of 91000091001 is 10019000019.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 91000091001 - 2¹⁰ = 91000089977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91000096001) 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, 15166681831 + ... + 15166681836.

It is an arithmetic number, because the mean of its divisors is an integer number (30333363668).

Almost surely, 2^91000091001 is an apocalyptic number.

It is an amenable number.

91000091001 is a deficient number, since it is larger than the sum of its proper divisors (30333363671).

91000091001 is a wasteful number, since it uses less digits than its factorization.

91000091001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30333363670.

The product of its (nonzero) digits is 81, while the sum is 21.

It can be divided in two parts, 910000 and 91001, that added together give a palindrome (1001001).

The spelling of 91000091001 in words is "ninety-one billion, ninety-one thousand, one".