31213113210221 has 2 divisors, whose sum is σ = 31213113210222. Its totient is φ = 31213113210220.

The previous prime is 31213113210217. The next prime is 31213113210271. The reversal of 31213113210221 is 12201231131213.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 23254287952900 + 7958825257321 = 4822270^2 + 2821139^2 .

It is a cyclic number.

It is not a de Polignac number, because 31213113210221 - 2² = 31213113210217 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31213113210271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15606556605110 + 15606556605111.

It is an arithmetic number, because the mean of its divisors is an integer number (15606556605111).

Almost surely, 2^{31213113210221} is an apocalyptic number.

It is an amenable number.

31213113210221 is a deficient number, since it is larger than the sum of its proper divisors (1).

31213113210221 is an equidigital number, since it uses as much as digits as its factorization.

31213113210221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 23.

Adding to 31213113210221 its reverse (12201231131213), we get a palindrome (43414344341434).

The spelling of 31213113210221 in words is "thirty-one trillion, two hundred thirteen billion, one hundred thirteen million, two hundred ten thousand, two hundred twenty-one".