728708469721 has 2 divisors, whose sum is σ = 728708469722. Its totient is φ = 728708469720.

The previous prime is 728708469719. The next prime is 728708469733. The reversal of 728708469721 is 127964807827.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 517875972496 + 210832497225 = 719636^2 + 459165^2 .

It is a cyclic number.

It is not a de Polignac number, because 728708469721 - 2¹ = 728708469719 is a prime.

Together with 728708469719, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 728708469721.

It is not a weakly prime, because it can be changed into another prime (728708460721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 364354234860 + 364354234861.

It is an arithmetic number, because the mean of its divisors is an integer number (364354234861).

Almost surely, 2^728708469721 is an apocalyptic number.

It is an amenable number.

728708469721 is a deficient number, since it is larger than the sum of its proper divisors (1).

728708469721 is an equidigital number, since it uses as much as digits as its factorization.

728708469721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18966528, while the sum is 61.

The spelling of 728708469721 in words is "seven hundred twenty-eight billion, seven hundred eight million, four hundred sixty-nine thousand, seven hundred twenty-one".