221311321213 has 4 divisors (see below), whose sum is σ = 222098906268. Its totient is φ = 220523736160.

The previous prime is 221311321199. The next prime is 221311321219. The reversal of 221311321213 is 312123113122.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 312123113122 = 2 ⋅156061556561.

It can be written as a sum of positive squares in 2 ways, for example, as 190966378009 + 30344943204 = 436997^2 + 174198^2 .

It is a cyclic number.

It is not a de Polignac number, because 221311321213 - 2⁵ = 221311321181 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 (221311321219) 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, 393792106 + ... + 393792667.

It is an arithmetic number, because the mean of its divisors is an integer number (55524726567).

Almost surely, 2^221311321213 is an apocalyptic number.

It is an amenable number.

221311321213 is a deficient number, since it is larger than the sum of its proper divisors (787585055).

221311321213 is an equidigital number, since it uses as much as digits as its factorization.

221311321213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 787585054.

The product of its digits is 432, while the sum is 22.

Adding to 221311321213 its reverse (312123113122), we get a palindrome (533434434335).

The spelling of 221311321213 in words is "two hundred twenty-one billion, three hundred eleven million, three hundred twenty-one thousand, two hundred thirteen".