221210121221 has 4 divisors (see below), whose sum is σ = 232852759200. Its totient is φ = 209567483244.

The previous prime is 221210121203. The next prime is 221210121227. The reversal of 221210121221 is 122121012122.

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 221210121221 - 2¹⁸ = 221209859077 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 221210121221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221210121227) 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, 5821318961 + ... + 5821318998.

It is an arithmetic number, because the mean of its divisors is an integer number (58213189800).

Almost surely, 2^221210121221 is an apocalyptic number.

It is an amenable number.

221210121221 is a deficient number, since it is larger than the sum of its proper divisors (11642637979).

221210121221 is a wasteful number, since it uses less digits than its factorization.

221210121221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11642637978.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 221210121221 its reverse (122121012122), we get a palindrome (343331133343).

It can be divided in two parts, 2212101 and 21221, that added together give a palindrome (2233322).

The spelling of 221210121221 in words is "two hundred twenty-one billion, two hundred ten million, one hundred twenty-one thousand, two hundred twenty-one".