231808133 has 2 divisors, whose sum is σ = 231808134. Its totient is φ = 231808132.

The previous prime is 231808121. The next prime is 231808139. The reversal of 231808133 is 331808132.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 218507524 + 13300609 = 14782^2 + 3647^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-231808133 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 231808096 and 231808105.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231808139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115904066 + 115904067.

It is an arithmetic number, because the mean of its divisors is an integer number (115904067).

Almost surely, 2^231808133 is an apocalyptic number.

It is an amenable number.

231808133 is a deficient number, since it is larger than the sum of its proper divisors (1).

231808133 is an equidigital number, since it uses as much as digits as its factorization.

231808133 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 231808133 is about 15225.2465661480. The cubic root of 231808133 is about 614.2939287037.

Subtracting 231808133 from its reverse (331808132), we obtain a palindrome (99999999).

It can be divided in two parts, 23180 and 8133, that added together give a palindrome (31313).

The spelling of 231808133 in words is "two hundred thirty-one million, eight hundred eight thousand, one hundred thirty-three".