31223221220221 has 16 divisors (see below), whose sum is σ = 32106287340288. Its totient is φ = 30345966489600.

The previous prime is 31223221220173. The next prime is 31223221220231. The reversal of 31223221220221 is 12202212232213.

It is a cyclic number.

It is not a de Polignac number, because 31223221220221 - 2¹⁵ = 31223221187453 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 (31223221220231) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 105039421 + ... + 105336253.

It is an arithmetic number, because the mean of its divisors is an integer number (2006642958768).

Almost surely, 2^{31223221220221} is an apocalyptic number.

It is an amenable number.

31223221220221 is a deficient number, since it is larger than the sum of its proper divisors (883066120067).

31223221220221 is a wasteful number, since it uses less digits than its factorization.

31223221220221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 306612.

The product of its (nonzero) digits is 2304, while the sum is 25.

Adding to 31223221220221 its reverse (12202212232213), we get a palindrome (43425433452434).

The spelling of 31223221220221 in words is "thirty-one trillion, two hundred twenty-three billion, two hundred twenty-one million, two hundred twenty thousand, two hundred twenty-one".