233131991 has 2 divisors, whose sum is σ = 233131992. Its totient is φ = 233131990.

The previous prime is 233131973. The next prime is 233131993. The reversal of 233131991 is 199131332.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-233131991 is a prime.

It is a Sophie Germain prime.

Together with 233131993, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (233131993) 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, 116565995 + 116565996.

It is an arithmetic number, because the mean of its divisors is an integer number (116565996).

Almost surely, 2^233131991 is an apocalyptic number.

233131991 is a deficient number, since it is larger than the sum of its proper divisors (1).

233131991 is an equidigital number, since it uses as much as digits as its factorization.

233131991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4374, while the sum is 32.

The square root of 233131991 is about 15268.6604193033. The cubic root of 233131991 is about 615.4611219893.

The spelling of 233131991 in words is "two hundred thirty-three million, one hundred thirty-one thousand, nine hundred ninety-one".