21202220221 has 16 divisors (see below), whose sum is σ = 26187936768. Its totient is φ = 16715664000.

The previous prime is 21202220219. The next prime is 21202220231. The reversal of 21202220221 is 12202220212.

It is not a de Polignac number, because 21202220221 - 2¹ = 21202220219 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21202220195 and 21202220204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21202220201) 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 15 ways as a sum of consecutive naturals, for example, 389005 + ... + 440146.

It is an arithmetic number, because the mean of its divisors is an integer number (1636746048).

Almost surely, 2^21202220221 is an apocalyptic number.

It is an amenable number.

21202220221 is a deficient number, since it is larger than the sum of its proper divisors (4985716547).

21202220221 is a wasteful number, since it uses less digits than its factorization.

21202220221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 829452.

The product of its (nonzero) digits is 128, while the sum is 16.

Adding to 21202220221 its reverse (12202220212), we get a palindrome (33404440433).

Subtracting from 21202220221 its reverse (12202220212), we obtain a palindrome (9000000009).

The spelling of 21202220221 in words is "twenty-one billion, two hundred two million, two hundred twenty thousand, two hundred twenty-one".