723437721 has 6 divisors (see below), whose sum is σ = 1044965610. Its totient is φ = 482291808.

The previous prime is 723437717. The next prime is 723437747. The reversal of 723437721 is 127734327.

It is a happy number.

723437721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 478953225 + 244484496 = 21885^2 + 15636^2 .

It is not a de Polignac number, because 723437721 - 2² = 723437717 is a prime.

It is not an unprimeable number, because it can be changed into a prime (723437761) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 40190976 + ... + 40190993.

It is an arithmetic number, because the mean of its divisors is an integer number (174160935).

Almost surely, 2^723437721 is an apocalyptic number.

It is an amenable number.

723437721 is a deficient number, since it is larger than the sum of its proper divisors (321527889).

723437721 is a wasteful number, since it uses less digits than its factorization.

723437721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80381975 (or 80381972 counting only the distinct ones).

The product of its digits is 49392, while the sum is 36.

The square root of 723437721 is about 26896.7975974836. The cubic root of 723437721 is about 897.7051497836.

The spelling of 723437721 in words is "seven hundred twenty-three million, four hundred thirty-seven thousand, seven hundred twenty-one".