31211222261 has 2 divisors, whose sum is σ = 31211222262. Its totient is φ = 31211222260.

The previous prime is 31211222191. The next prime is 31211222269. The reversal of 31211222261 is 16222211213.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 26448842161 + 4762380100 = 162631^2 + 69010^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31211222261 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31211222269) 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, 15605611130 + 15605611131.

It is an arithmetic number, because the mean of its divisors is an integer number (15605611131).

Almost surely, 2^31211222261 is an apocalyptic number.

It is an amenable number.

31211222261 is a deficient number, since it is larger than the sum of its proper divisors (1).

31211222261 is an equidigital number, since it uses as much as digits as its factorization.

31211222261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 576, while the sum is 23.

Adding to 31211222261 its reverse (16222211213), we get a palindrome (47433433474).

The spelling of 31211222261 in words is "thirty-one billion, two hundred eleven million, two hundred twenty-two thousand, two hundred sixty-one".