21210200221 has 24 divisors (see below), whose sum is σ = 25564883040. Its totient is φ = 17534698272.

The previous prime is 21210200201. The next prime is 21210200239. The reversal of 21210200221 is 12200201212.

It is a happy number.

It is not a de Polignac number, because 21210200221 - 2⁵ = 21210200189 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 (21210200201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 84010 + ... + 222436.

It is an arithmetic number, because the mean of its divisors is an integer number (1065203460).

Almost surely, 2^21210200221 is an apocalyptic number.

It is an amenable number.

21210200221 is a deficient number, since it is larger than the sum of its proper divisors (4354682819).

21210200221 is a wasteful number, since it uses less digits than its factorization.

21210200221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138553 (or 138546 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21210200221 its reverse (12200201212), we get a palindrome (33410401433).

Subtracting from 21210200221 its reverse (12200201212), we obtain a palindrome (9009999009).

The spelling of 21210200221 in words is "twenty-one billion, two hundred ten million, two hundred thousand, two hundred twenty-one".