221323210091 has 4 divisors (see below), whose sum is σ = 225074451000. Its totient is φ = 217571969184.

The previous prime is 221323210037. The next prime is 221323210117. The reversal of 221323210091 is 190012323122.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 190012323122 = 2 ⋅95006161561.

It is a cyclic number.

It is not a de Polignac number, because 221323210091 - 2¹⁸ = 221322947947 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 221323210091.

It is not an unprimeable number, because it can be changed into a prime (221323210021) 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, 1875620366 + ... + 1875620483.

It is an arithmetic number, because the mean of its divisors is an integer number (56268612750).

Almost surely, 2^221323210091 is an apocalyptic number.

221323210091 is a deficient number, since it is larger than the sum of its proper divisors (3751240909).

221323210091 is an equidigital number, since it uses as much as digits as its factorization.

221323210091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3751240908.

The product of its (nonzero) digits is 1296, while the sum is 26.

The spelling of 221323210091 in words is "two hundred twenty-one billion, three hundred twenty-three million, two hundred ten thousand, ninety-one".