20212220221 has 8 divisors (see below), whose sum is σ = 20750527224. Its totient is φ = 19676071680.

The previous prime is 20212220183. The next prime is 20212220267. The reversal of 20212220221 is 12202221202.

It can be written as a sum of positive squares in 4 ways, for example, as 7440960121 + 12771260100 = 86261^2 + 113010^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20212220221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20212220195 and 20212220204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20212220321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 520630 + ... + 558103.

It is an arithmetic number, because the mean of its divisors is an integer number (2593815903).

Almost surely, 2^20212220221 is an apocalyptic number.

It is an amenable number.

20212220221 is a deficient number, since it is larger than the sum of its proper divisors (538307003).

20212220221 is a wasteful number, since it uses less digits than its factorization.

20212220221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1079231.

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

Adding to 20212220221 its reverse (12202221202), we get a palindrome (32414441423).

The spelling of 20212220221 in words is "twenty billion, two hundred twelve million, two hundred twenty thousand, two hundred twenty-one".