31012213261 has 2 divisors, whose sum is σ = 31012213262. Its totient is φ = 31012213260.

The previous prime is 31012213187. The next prime is 31012213273. The reversal of 31012213261 is 16231221013.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22271085225 + 8741128036 = 149235^2 + 93494^2 .

It is a cyclic number.

It is not a de Polignac number, because 31012213261 - 2²³ = 31003824653 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31012213291) 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, 15506106630 + 15506106631.

It is an arithmetic number, because the mean of its divisors is an integer number (15506106631).

Almost surely, 2^31012213261 is an apocalyptic number.

It is an amenable number.

31012213261 is a deficient number, since it is larger than the sum of its proper divisors (1).

31012213261 is an equidigital number, since it uses as much as digits as its factorization.

31012213261 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 22.

Adding to 31012213261 its reverse (16231221013), we get a palindrome (47243434274).

The spelling of 31012213261 in words is "thirty-one billion, twelve million, two hundred thirteen thousand, two hundred sixty-one".