91220211 has 6 divisors (see below), whose sum is σ = 131762540. Its totient is φ = 60813468.

The previous prime is 91220209. The next prime is 91220221. The reversal of 91220211 is 11202219.

It is not a de Polignac number, because 91220211 - 2¹ = 91220209 is a prime.

It is a super-2 number, since 2×91220211² = 16642253789769042, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91220201) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 5067781 + ... + 5067798.

Almost surely, 2^91220211 is an apocalyptic number.

91220211 is a deficient number, since it is larger than the sum of its proper divisors (40542329).

91220211 is a wasteful number, since it uses less digits than its factorization.

91220211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10135585 (or 10135582 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 91220211 is about 9550.9272324733. The cubic root of 91220211 is about 450.1566713731.

The spelling of 91220211 in words is "ninety-one million, two hundred twenty thousand, two hundred eleven".