20210221221 has 4 divisors (see below), whose sum is σ = 26946961632. Its totient is φ = 13473480812.

The previous prime is 20210221219. The next prime is 20210221259. The reversal of 20210221221 is 12212201202.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20210221221 - 2¹ = 20210221219 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20210221221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20210221621) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3368370201 + ... + 3368370206.

It is an arithmetic number, because the mean of its divisors is an integer number (6736740408).

Almost surely, 2^20210221221 is an apocalyptic number.

It is an amenable number.

20210221221 is a deficient number, since it is larger than the sum of its proper divisors (6736740411).

20210221221 is an equidigital number, since it uses as much as digits as its factorization.

20210221221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6736740410.

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

Adding to 20210221221 its reverse (12212201202), we get a palindrome (32422422423).

The spelling of 20210221221 in words is "twenty billion, two hundred ten million, two hundred twenty-one thousand, two hundred twenty-one".