21211020221 has 8 divisors (see below), whose sum is σ = 21312244800. Its totient is φ = 21109952032.

The previous prime is 21211020191. The next prime is 21211020269. The reversal of 21211020221 is 12202011212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21211020221 - 2¹⁸ = 21210758077 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21211020196 and 21211020205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211020421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 237446 + ... + 314328.

It is an arithmetic number, because the mean of its divisors is an integer number (2664030600).

Almost surely, 2^21211020221 is an apocalyptic number.

It is an amenable number.

21211020221 is a deficient number, since it is larger than the sum of its proper divisors (101224579).

21211020221 is a wasteful number, since it uses less digits than its factorization.

21211020221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78195.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21211020221 its reverse (12202011212), we get a palindrome (33413031433).

Subtracting from 21211020221 its reverse (12202011212), we obtain a palindrome (9009009009).

The spelling of 21211020221 in words is "twenty-one billion, two hundred eleven million, twenty thousand, two hundred twenty-one".