68391931 has 2 divisors, whose sum is σ = 68391932. Its totient is φ = 68391930.

The previous prime is 68391929. The next prime is 68391937. The reversal of 68391931 is 13919386.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 68391931 - 2¹ = 68391929 is a prime.

It is a super-2 number, since 2×68391931² = 9354912451817522, which contains 22 as substring.

Together with 68391929, 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 (68391937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34195965 + 34195966.

It is an arithmetic number, because the mean of its divisors is an integer number (34195966).

Almost surely, 2^68391931 is an apocalyptic number.

68391931 is a deficient number, since it is larger than the sum of its proper divisors (1).

68391931 is an equidigital number, since it uses as much as digits as its factorization.

68391931 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 34992, while the sum is 40.

The square root of 68391931 is about 8269.9414145446. The cubic root of 68391931 is about 408.9481883902.

The spelling of 68391931 in words is "sixty-eight million, three hundred ninety-one thousand, nine hundred thirty-one".