91223213 has 4 divisors (see below), whose sum is σ = 91297500. Its totient is φ = 91148928.

The previous prime is 91223203. The next prime is 91223227. The reversal of 91223213 is 31232219.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31232219 = 19 ⋅1643801.

It can be written as a sum of positive squares in 2 ways, for example, as 67535524 + 23687689 = 8218^2 + 4867^2 .

It is a cyclic number.

It is not a de Polignac number, because 91223213 - 2¹⁰ = 91222189 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91223203) 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, 35270 + ... + 37767.

It is an arithmetic number, because the mean of its divisors is an integer number (22824375).

Almost surely, 2^91223213 is an apocalyptic number.

It is an amenable number.

91223213 is a deficient number, since it is larger than the sum of its proper divisors (74287).

91223213 is a wasteful number, since it uses less digits than its factorization.

91223213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74286.

The product of its digits is 648, while the sum is 23.

The square root of 91223213 is about 9551.0843886964. The cubic root of 91223213 is about 450.1616094436.

The spelling of 91223213 in words is "ninety-one million, two hundred twenty-three thousand, two hundred thirteen".