68725721 has 2 divisors, whose sum is σ = 68725722. Its totient is φ = 68725720.

The previous prime is 68725693. The next prime is 68725733. The reversal of 68725721 is 12752786.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 52765696 + 15960025 = 7264^2 + 3995^2 .

It is a cyclic number.

It is not a de Polignac number, because 68725721 - 2¹⁰ = 68724697 is a prime.

It is not a weakly prime, because it can be changed into another prime (68725751) 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, 34362860 + 34362861.

It is an arithmetic number, because the mean of its divisors is an integer number (34362861).

Almost surely, 2^68725721 is an apocalyptic number.

It is an amenable number.

68725721 is a deficient number, since it is larger than the sum of its proper divisors (1).

68725721 is an equidigital number, since it uses as much as digits as its factorization.

68725721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 47040, while the sum is 38.

The square root of 68725721 is about 8290.0977678191. The cubic root of 68725721 is about 409.6124058622.

The spelling of 68725721 in words is "sixty-eight million, seven hundred twenty-five thousand, seven hundred twenty-one".