68405921 has 2 divisors, whose sum is σ = 68405922. Its totient is φ = 68405920.

The previous prime is 68405903. The next prime is 68405951. The reversal of 68405921 is 12950486.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 68293696 + 112225 = 8264^2 + 335^2 .

It is a cyclic number.

It is not a de Polignac number, because 68405921 - 2¹⁴ = 68389537 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (68405951) 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, 34202960 + 34202961.

It is an arithmetic number, because the mean of its divisors is an integer number (34202961).

Almost surely, 2^68405921 is an apocalyptic number.

It is an amenable number.

68405921 is a deficient number, since it is larger than the sum of its proper divisors (1).

68405921 is an equidigital number, since it uses as much as digits as its factorization.

68405921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17280, while the sum is 35.

The square root of 68405921 is about 8270.7872055809. The cubic root of 68405921 is about 408.9760707979.

The spelling of 68405921 in words is "sixty-eight million, four hundred five thousand, nine hundred twenty-one".