31991709818911 has 2 divisors, whose sum is σ = 31991709818912. Its totient is φ = 31991709818910.

The previous prime is 31991709818869. The next prime is 31991709818917. The reversal of 31991709818911 is 11981890719913.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 31991709818911 - 2¹³ = 31991709810719 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31991709818917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15995854909455 + 15995854909456.

It is an arithmetic number, because the mean of its divisors is an integer number (15995854909456).

Almost surely, 2^{31991709818911} is an apocalyptic number.

31991709818911 is a deficient number, since it is larger than the sum of its proper divisors (1).

31991709818911 is an equidigital number, since it uses as much as digits as its factorization.

31991709818911 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8817984, while the sum is 67.

The spelling of 31991709818911 in words is "thirty-one trillion, nine hundred ninety-one billion, seven hundred nine million, eight hundred eighteen thousand, nine hundred eleven".