20212331221 has 4 divisors (see below), whose sum is σ = 20212746700. Its totient is φ = 20211915744.

The previous prime is 20212331213. The next prime is 20212331239. The reversal of 20212331221 is 12213321202.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19682687025 + 529644196 = 140295^2 + 23014^2 .

It is a cyclic number.

It is not a de Polignac number, because 20212331221 - 2³ = 20212331213 is a prime.

It is a super-2 number, since 2×20212331221² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20212331261) 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, 123336 + ... + 235873.

It is an arithmetic number, because the mean of its divisors is an integer number (5053186675).

Almost surely, 2^20212331221 is an apocalyptic number.

It is an amenable number.

20212331221 is a deficient number, since it is larger than the sum of its proper divisors (415479).

20212331221 is an equidigital number, since it uses as much as digits as its factorization.

20212331221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 415478.

The product of its (nonzero) digits is 288, while the sum is 19.

Adding to 20212331221 its reverse (12213321202), we get a palindrome (32425652423).

The spelling of 20212331221 in words is "twenty billion, two hundred twelve million, three hundred thirty-one thousand, two hundred twenty-one".