725785721 has 2 divisors, whose sum is σ = 725785722. Its totient is φ = 725785720.

The previous prime is 725785717. The next prime is 725785789. The reversal of 725785721 is 127587527.

725785721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 638269696 + 87516025 = 25264^2 + 9355^2 .

It is a cyclic number.

It is not a de Polignac number, because 725785721 - 2² = 725785717 is a prime.

It is not a weakly prime, because it can be changed into another prime (725782721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 362892860 + 362892861.

It is an arithmetic number, because the mean of its divisors is an integer number (362892861).

Almost surely, 2^725785721 is an apocalyptic number.

It is an amenable number.

725785721 is a deficient number, since it is larger than the sum of its proper divisors (1).

725785721 is an equidigital number, since it uses as much as digits as its factorization.

725785721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 274400, while the sum is 44.

The square root of 725785721 is about 26940.4105573764. The cubic root of 725785721 is about 898.6753025934.

The spelling of 725785721 in words is "seven hundred twenty-five million, seven hundred eighty-five thousand, seven hundred twenty-one".