68721519409 has 2 divisors, whose sum is σ = 68721519410. Its totient is φ = 68721519408.

The previous prime is 68721519371. The next prime is 68721519467. The reversal of 68721519409 is 90491512786.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 67275390625 + 1446128784 = 259375^2 + 38028^2 .

It is a cyclic number.

It is not a de Polignac number, because 68721519409 - 2¹⁹ = 68720995121 is a prime.

It is not a weakly prime, because it can be changed into another prime (68721519509) 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, 34360759704 + 34360759705.

It is an arithmetic number, because the mean of its divisors is an integer number (34360759705).

Almost surely, 2^68721519409 is an apocalyptic number.

It is an amenable number.

68721519409 is a deficient number, since it is larger than the sum of its proper divisors (1).

68721519409 is an equidigital number, since it uses as much as digits as its factorization.

68721519409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1088640, while the sum is 52.

The spelling of 68721519409 in words is "sixty-eight billion, seven hundred twenty-one million, five hundred nineteen thousand, four hundred nine".