31311243391 has 2 divisors, whose sum is σ = 31311243392. Its totient is φ = 31311243390.

The previous prime is 31311243389. The next prime is 31311243449. The reversal of 31311243391 is 19334211313.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 31311243391 - 2¹ = 31311243389 is a prime.

It is a super-3 number, since 3×31311243391³ (a number of 32 digits) contains 333 as substring.

Together with 31311243389, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31311243371) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15655621695 + 15655621696.

It is an arithmetic number, because the mean of its divisors is an integer number (15655621696).

Almost surely, 2^31311243391 is an apocalyptic number.

31311243391 is a deficient number, since it is larger than the sum of its proper divisors (1).

31311243391 is an equidigital number, since it uses as much as digits as its factorization.

31311243391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5832, while the sum is 31.

The spelling of 31311243391 in words is "thirty-one billion, three hundred eleven million, two hundred forty-three thousand, three hundred ninety-one".