21000211210221 has 16 divisors (see below), whose sum is σ = 28013848498944. Its totient is φ = 13993359015744.

The previous prime is 21000211210189. The next prime is 21000211210247. The reversal of 21000211210221 is 12201211200012.

It is not a de Polignac number, because 21000211210221 - 2⁵ = 21000211210189 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21000211210221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000211210021) 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, 51706875 + ... + 52111431.

It is an arithmetic number, because the mean of its divisors is an integer number (1750865531184).

Almost surely, 2^{21000211210221} is an apocalyptic number.

It is an amenable number.

21000211210221 is a deficient number, since it is larger than the sum of its proper divisors (7013637288723).

21000211210221 is a wasteful number, since it uses less digits than its factorization.

21000211210221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 412900.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21000211210221 its reverse (12201211200012), we get a palindrome (33201422410233).

The spelling of 21000211210221 in words is "twenty-one trillion, two hundred eleven million, two hundred ten thousand, two hundred twenty-one".