31122212161 has 2 divisors, whose sum is σ = 31122212162. Its totient is φ = 31122212160.

The previous prime is 31122212117. The next prime is 31122212197. The reversal of 31122212161 is 16121222113.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19305435136 + 11816777025 = 138944^2 + 108705^2 .

It is a cyclic number.

It is not a de Polignac number, because 31122212161 - 2⁹ = 31122211649 is a prime.

It is a super-3 number, since 3×31122212161³ (a number of 32 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (31122212861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15561106080 + 15561106081.

It is an arithmetic number, because the mean of its divisors is an integer number (15561106081).

Almost surely, 2^31122212161 is an apocalyptic number.

It is an amenable number.

31122212161 is a deficient number, since it is larger than the sum of its proper divisors (1).

31122212161 is an equidigital number, since it uses as much as digits as its factorization.

31122212161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 288, while the sum is 22.

Adding to 31122212161 its reverse (16121222113), we get a palindrome (47243434274).

The spelling of 31122212161 in words is "thirty-one billion, one hundred twenty-two million, two hundred twelve thousand, one hundred sixty-one".