68729021 has 2 divisors, whose sum is σ = 68729022. Its totient is φ = 68729020.

The previous prime is 68728987. The next prime is 68729039. The reversal of 68729021 is 12092786.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 52041796 + 16687225 = 7214^2 + 4085^2 .

It is a cyclic number.

It is not a de Polignac number, because 68729021 - 2¹⁸ = 68466877 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (68729321) 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, 34364510 + 34364511.

It is an arithmetic number, because the mean of its divisors is an integer number (34364511).

Almost surely, 2^68729021 is an apocalyptic number.

It is an amenable number.

68729021 is a deficient number, since it is larger than the sum of its proper divisors (1).

68729021 is an equidigital number, since it uses as much as digits as its factorization.

68729021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12096, while the sum is 35.

The square root of 68729021 is about 8290.2967980646. The cubic root of 68729021 is about 409.6189618710.

The spelling of 68729021 in words is "sixty-eight million, seven hundred twenty-nine thousand, twenty-one".