231808121 has 2 divisors, whose sum is σ = 231808122. Its totient is φ = 231808120.

The previous prime is 231808097. The next prime is 231808133. The reversal of 231808121 is 121808132.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 138415225 + 93392896 = 11765^2 + 9664^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-231808121 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (231808321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115904060 + 115904061.

It is an arithmetic number, because the mean of its divisors is an integer number (115904061).

Almost surely, 2^231808121 is an apocalyptic number.

It is an amenable number.

231808121 is a deficient number, since it is larger than the sum of its proper divisors (1).

231808121 is an equidigital number, since it uses as much as digits as its factorization.

231808121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 768, while the sum is 26.

The square root of 231808121 is about 15225.2461720657. The cubic root of 231808121 is about 614.2939181036.

The spelling of 231808121 in words is "two hundred thirty-one million, eight hundred eight thousand, one hundred twenty-one".