231668681 has 2 divisors, whose sum is σ = 231668682. Its totient is φ = 231668680.

The previous prime is 231668629. The next prime is 231668683. The reversal of 231668681 is 186866132.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 159163456 + 72505225 = 12616^2 + 8515^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-231668681 is a prime.

It is a super-2 number, since 2×231668681² = 107340755512559522, which contains 22 as substring.

Together with 231668683, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (231668683) 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, 115834340 + 115834341.

It is an arithmetic number, because the mean of its divisors is an integer number (115834341).

Almost surely, 2^231668681 is an apocalyptic number.

It is an amenable number.

231668681 is a deficient number, since it is larger than the sum of its proper divisors (1).

231668681 is an equidigital number, since it uses as much as digits as its factorization.

231668681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 82944, while the sum is 41.

The square root of 231668681 is about 15220.6662469157. Note that the first 3 decimals coincide. The cubic root of 231668681 is about 614.1707209173.

The spelling of 231668681 in words is "two hundred thirty-one million, six hundred sixty-eight thousand, six hundred eighty-one".