31110312221 has 2 divisors, whose sum is σ = 31110312222. Its totient is φ = 31110312220.

The previous prime is 31110312179. The next prime is 31110312241. The reversal of 31110312221 is 12221301113.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28227696121 + 2882616100 = 168011^2 + 53690^2 .

It is a cyclic number.

It is not a de Polignac number, because 31110312221 - 2¹⁸ = 31110050077 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31110312221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31110312241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15555156110 + 15555156111.

It is an arithmetic number, because the mean of its divisors is an integer number (15555156111).

Almost surely, 2^31110312221 is an apocalyptic number.

It is an amenable number.

31110312221 is a deficient number, since it is larger than the sum of its proper divisors (1).

31110312221 is an equidigital number, since it uses as much as digits as its factorization.

31110312221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 31110312221 its reverse (12221301113), we get a palindrome (43331613334).

The spelling of 31110312221 in words is "thirty-one billion, one hundred ten million, three hundred twelve thousand, two hundred twenty-one".