21212220220221 has 8 divisors (see below), whose sum is σ = 29946663840384. Its totient is φ = 13309628373440.

The previous prime is 21212220220189. The next prime is 21212220220259. The reversal of 21212220220221 is 12202202221212.

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 21212220220221 - 2⁵ = 21212220220189 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212220220621) 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, 207962943285 + ... + 207962943386.

It is an arithmetic number, because the mean of its divisors is an integer number (3743332980048).

Almost surely, 2^{21212220220221} is an apocalyptic number.

It is an amenable number.

21212220220221 is a deficient number, since it is larger than the sum of its proper divisors (8734443620163).

21212220220221 is a wasteful number, since it uses less digits than its factorization.

21212220220221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 415925886691.

The product of its (nonzero) digits is 512, while the sum is 21.

Adding to 21212220220221 its reverse (12202202221212), we get a palindrome (33414422441433).

The spelling of 21212220220221 in words is "twenty-one trillion, two hundred twelve billion, two hundred twenty million, two hundred twenty thousand, two hundred twenty-one".