21202201221 has 16 divisors (see below), whose sum is σ = 29048110080. Its totient is φ = 13748298480.

The previous prime is 21202201201. The next prime is 21202201247. The reversal of 21202201221 is 12210220212.

It is not a de Polignac number, because 21202201221 - 2⁷ = 21202201093 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21202201221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21202201201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 313015 + ... + 374676.

It is an arithmetic number, because the mean of its divisors is an integer number (1815506880).

Almost surely, 2^21202201221 is an apocalyptic number.

It is an amenable number.

21202201221 is a deficient number, since it is larger than the sum of its proper divisors (7845908859).

21202201221 is a wasteful number, since it uses less digits than its factorization.

21202201221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 687976.

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21202201221 its reverse (12210220212), we get a palindrome (33412421433).

The spelling of 21202201221 in words is "twenty-one billion, two hundred two million, two hundred one thousand, two hundred twenty-one".