221321213121213 has 24 divisors (see below), whose sum is σ = 330710578263000. Its totient is φ = 142459321463424.

The previous prime is 221321213121179. The next prime is 221321213121269. The reversal of 221321213121213 is 312121312123122.

221321213121213 is a `hidden beast` number, since 2 + 2 + 1 + 321 + 2 + 1 + 3 + 121 + 213 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 79336305710649 + 141984907410564 = 8907093^2 + 11915742^2 .

It is not a de Polignac number, because 221321213121213 - 2⁶ = 221321213121149 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221321213121713) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 225776263 + ... + 226754411.

It is an arithmetic number, because the mean of its divisors is an integer number (13779607427625).

Almost surely, 2^{221321213121213} is an apocalyptic number.

It is an amenable number.

221321213121213 is a deficient number, since it is larger than the sum of its proper divisors (109389365141787).

221321213121213 is a wasteful number, since it uses less digits than its factorization.

221321213121213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1845101 (or 1845098 counting only the distinct ones).

The product of its digits is 1728, while the sum is 27.

Adding to 221321213121213 its reverse (312121312123122), we get a palindrome (533442525244335).

The spelling of 221321213121213 in words is "two hundred twenty-one trillion, three hundred twenty-one billion, two hundred thirteen million, one hundred twenty-one thousand, two hundred thirteen".