21202201221021 has 24 divisors (see below), whose sum is σ = 31462019735640. Its totient is φ = 13748885744256.

The previous prime is 21202201220969. The next prime is 21202201221029. The reversal of 21202201221021 is 12012210220212.

It is a happy number.

21202201221021 is a `hidden beast` number, since 21 + 202 + 201 + 221 + 0 + 21 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 5163738132996 + 16038463088025 = 2272386^2 + 4004805^2 .

It is not a de Polignac number, because 21202201221021 - 2¹⁵ = 21202201188253 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21202201220985 and 21202201221003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21202201221029) 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, 7834306 + ... + 10187283.

It is an arithmetic number, because the mean of its divisors is an integer number (1310917488985).

Almost surely, 2^{21202201221021} is an apocalyptic number.

It is an amenable number.

21202201221021 is a deficient number, since it is larger than the sum of its proper divisors (10259818514619).

21202201221021 is a wasteful number, since it uses less digits than its factorization.

21202201221021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18025165 (or 18025162 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21202201221021 its reverse (12012210220212), we get a palindrome (33214411441233).

The spelling of 21202201221021 in words is "twenty-one trillion, two hundred two billion, two hundred one million, two hundred twenty-one thousand, twenty-one".