68000021 has 2 divisors, whose sum is σ = 68000022. Its totient is φ = 68000020.

The previous prime is 68000003. The next prime is 68000039. The reversal of 68000021 is 12000086.

It is a balanced prime because it is at equal distance from previous prime (68000003) and next prime (68000039).

It can be written as a sum of positive squares in only one way, i.e., 63377521 + 4622500 = 7961^2 + 2150^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-68000021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (68000521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34000010 + 34000011.

It is an arithmetic number, because the mean of its divisors is an integer number (34000011).

Almost surely, 2^68000021 is an apocalyptic number.

It is an amenable number.

68000021 is a deficient number, since it is larger than the sum of its proper divisors (1).

68000021 is an equidigital number, since it uses as much as digits as its factorization.

68000021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 68000021 is about 8246.2125245473. The cubic root of 68000021 is about 408.1655522088.

The spelling of 68000021 in words is "sixty-eight million, twenty-one", and thus it is an aban number and an uban number.