91011021 has 12 divisors (see below), whose sum is σ = 124386816. Its totient is φ = 59190880.

The previous prime is 91010993. The next prime is 91011029. The reversal of 91011021 is 12011019.

It is not a de Polignac number, because 91011021 - 2⁵ = 91010989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91011029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3981 + ... + 14066.

It is an arithmetic number, because the mean of its divisors is an integer number (10365568).

Almost surely, 2^91011021 is an apocalyptic number.

It is an amenable number.

91011021 is a deficient number, since it is larger than the sum of its proper divisors (33375795).

91011021 is a wasteful number, since it uses less digits than its factorization.

91011021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18132 (or 18091 counting only the distinct ones).

The product of its (nonzero) digits is 18, while the sum is 15.

The square root of 91011021 is about 9539.9696540398. The cubic root of 91011021 is about 449.8123019677.

The spelling of 91011021 in words is "ninety-one million, eleven thousand, twenty-one".