212121212220221 has 8 divisors (see below), whose sum is σ = 216813826293120. Its totient is φ = 207478786533408.

The previous prime is 212121212220199. The next prime is 212121212220233. The reversal of 212121212220221 is 122022212121212.

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 212121212220221 - 2¹⁰ = 212121212219197 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212121212220721) 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, 12547087976 + ... + 12547104881.

It is an arithmetic number, because the mean of its divisors is an integer number (27101728286640).

Almost surely, 2^{212121212220221} is an apocalyptic number.

It is an amenable number.

212121212220221 is a deficient number, since it is larger than the sum of its proper divisors (4692614072899).

212121212220221 is a wasteful number, since it uses less digits than its factorization.

212121212220221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25094193043.

The product of its (nonzero) digits is 512, while the sum is 23.

Adding to 212121212220221 its reverse (122022212121212), we get a palindrome (334143424341433).

Subtracting from 212121212220221 its reverse (122022212121212), we obtain a palindrome (90099000099009).

The spelling of 212121212220221 in words is "two hundred twelve trillion, one hundred twenty-one billion, two hundred twelve million, two hundred twenty thousand, two hundred twenty-one".