213211211421521 has 16 divisors (see below), whose sum is σ = 214308954608400. Its totient is φ = 212115764544768.

The previous prime is 213211211421499. The next prime is 213211211421547. The reversal of 213211211421521 is 125124112112312.

It can be written as a sum of positive squares in 8 ways, for example, as 785279545600 + 212425931875921 = 886160^2 + 14574839^2 .

It is a cyclic number.

It is not a de Polignac number, because 213211211421521 - 2¹⁸ = 213211211159377 is a prime.

It is not an unprimeable number, because it can be changed into a prime (213211231421521) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5581864595 + ... + 5581902791.

It is an arithmetic number, because the mean of its divisors is an integer number (13394309663025).

Almost surely, 2^{213211211421521} is an apocalyptic number.

It is an amenable number.

213211211421521 is a deficient number, since it is larger than the sum of its proper divisors (1097743186879).

213211211421521 is a wasteful number, since it uses less digits than its factorization.

213211211421521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67508.

The product of its digits is 1920, while the sum is 29.

Adding to 213211211421521 its reverse (125124112112312), we get a palindrome (338335323533833).

The spelling of 213211211421521 in words is "two hundred thirteen trillion, two hundred eleven billion, two hundred eleven million, four hundred twenty-one thousand, five hundred twenty-one".