68681729 has 2 divisors, whose sum is σ = 68681730. Its totient is φ = 68681728.

The previous prime is 68681719. The next prime is 68681741. The reversal of 68681729 is 92718686.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 59367025 + 9314704 = 7705^2 + 3052^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-68681729 is a prime.

It is not a weakly prime, because it can be changed into another prime (68681719) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34340864 + 34340865.

It is an arithmetic number, because the mean of its divisors is an integer number (34340865).

It is a Proth number, since it is equal to 131 ⋅ 2¹⁹ + 1 and 131 < 2¹⁹.

Almost surely, 2^68681729 is an apocalyptic number.

It is an amenable number.

68681729 is a deficient number, since it is larger than the sum of its proper divisors (1).

68681729 is an equidigital number, since it uses as much as digits as its factorization.

68681729 is an evil number, because the sum of its binary digits is even.

The product of its digits is 290304, while the sum is 47.

The square root of 68681729 is about 8287.4440571264. Note that the first 3 decimals coincide. The cubic root of 68681729 is about 409.5249882504.

The spelling of 68681729 in words is "sixty-eight million, six hundred eighty-one thousand, seven hundred twenty-nine".