31122220121 has 2 divisors, whose sum is σ = 31122220122. Its totient is φ = 31122220120.

The previous prime is 31122220117. The next prime is 31122220133. The reversal of 31122220121 is 12102222113.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 30024225625 + 1097994496 = 173275^2 + 33136^2 .

It is a cyclic number.

It is not a de Polignac number, because 31122220121 - 2² = 31122220117 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31122220121.

It is not a weakly prime, because it can be changed into another prime (31122220111) 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, 15561110060 + 15561110061.

It is an arithmetic number, because the mean of its divisors is an integer number (15561110061).

Almost surely, 2^31122220121 is an apocalyptic number.

It is an amenable number.

31122220121 is a deficient number, since it is larger than the sum of its proper divisors (1).

31122220121 is an equidigital number, since it uses as much as digits as its factorization.

31122220121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 31122220121 its reverse (12102222113), we get a palindrome (43224442234).

The spelling of 31122220121 in words is "thirty-one billion, one hundred twenty-two million, two hundred twenty thousand, one hundred twenty-one".