68378021 has 2 divisors, whose sum is σ = 68378022. Its totient is φ = 68378020.

The previous prime is 68377993. The next prime is 68378047. The reversal of 68378021 is 12087386.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 60621796 + 7756225 = 7786^2 + 2785^2 .

It is a cyclic number.

It is not a de Polignac number, because 68378021 - 2¹⁸ = 68115877 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (68378081) 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, 34189010 + 34189011.

It is an arithmetic number, because the mean of its divisors is an integer number (34189011).

Almost surely, 2^68378021 is an apocalyptic number.

It is an amenable number.

68378021 is a deficient number, since it is larger than the sum of its proper divisors (1).

68378021 is an equidigital number, since it uses as much as digits as its factorization.

68378021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16128, while the sum is 35.

The square root of 68378021 is about 8269.1003742850. The cubic root of 68378021 is about 408.9204616545.

The spelling of 68378021 in words is "sixty-eight million, three hundred seventy-eight thousand, twenty-one".