91021200211 has 4 divisors (see below), whose sum is σ = 91826697672. Its totient is φ = 90215702752.

The previous prime is 91021200197. The next prime is 91021200217. The reversal of 91021200211 is 11200212019.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 11200212019 = 1061 ⋅10556279.

It is a cyclic number.

It is not a de Polignac number, because 91021200211 - 2⁹ = 91021199699 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91021200217) 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 3 ways as a sum of consecutive naturals, for example, 402748561 + ... + 402748786.

It is an arithmetic number, because the mean of its divisors is an integer number (22956674418).

Almost surely, 2^91021200211 is an apocalyptic number.

91021200211 is a deficient number, since it is larger than the sum of its proper divisors (805497461).

91021200211 is a wasteful number, since it uses less digits than its factorization.

91021200211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 805497460.

The product of its (nonzero) digits is 72, while the sum is 19.

The spelling of 91021200211 in words is "ninety-one billion, twenty-one million, two hundred thousand, two hundred eleven".