31991999233 has 2 divisors, whose sum is σ = 31991999234. Its totient is φ = 31991999232.

The previous prime is 31991999213. The next prime is 31991999261. The reversal of 31991999233 is 33299919913.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18239042704 + 13752956529 = 135052^2 + 117273^2 .

It is a cyclic number.

It is not a de Polignac number, because 31991999233 - 2²⁵ = 31958444801 is a prime.

It is not a weakly prime, because it can be changed into another prime (31991999203) 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, 15995999616 + 15995999617.

It is an arithmetic number, because the mean of its divisors is an integer number (15995999617).

Almost surely, 2^31991999233 is an apocalyptic number.

It is an amenable number.

31991999233 is a deficient number, since it is larger than the sum of its proper divisors (1).

31991999233 is an equidigital number, since it uses as much as digits as its factorization.

31991999233 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3188646, while the sum is 58.

The spelling of 31991999233 in words is "thirty-one billion, nine hundred ninety-one million, nine hundred ninety-nine thousand, two hundred thirty-three".