728523421 has 2 divisors, whose sum is σ = 728523422. Its totient is φ = 728523420.

The previous prime is 728523407. The next prime is 728523449. The reversal of 728523421 is 124325827.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 586317796 + 142205625 = 24214^2 + 11925^2 .

It is an emirp because it is prime and its reverse (124325827) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 728523421 - 2⁷ = 728523293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (728523461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 364261710 + 364261711.

It is an arithmetic number, because the mean of its divisors is an integer number (364261711).

Almost surely, 2^728523421 is an apocalyptic number.

It is an amenable number.

728523421 is a deficient number, since it is larger than the sum of its proper divisors (1).

728523421 is an equidigital number, since it uses as much as digits as its factorization.

728523421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 26880, while the sum is 34.

The square root of 728523421 is about 26991.1730200820. The cubic root of 728523421 is about 899.8038342011.

The spelling of 728523421 in words is "seven hundred twenty-eight million, five hundred twenty-three thousand, four hundred twenty-one".