728051521 has 4 divisors (see below), whose sum is σ = 731747412. Its totient is φ = 724355632.

The previous prime is 728051507. The next prime is 728051549. The reversal of 728051521 is 125150827.

728051521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 494573121 + 233478400 = 22239^2 + 15280^2 .

It is a cyclic number.

It is not a de Polignac number, because 728051521 - 2⁷ = 728051393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (728051501) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1847650 + ... + 1848043.

It is an arithmetic number, because the mean of its divisors is an integer number (182936853).

Almost surely, 2^728051521 is an apocalyptic number.

It is an amenable number.

728051521 is a deficient number, since it is larger than the sum of its proper divisors (3695891).

728051521 is a wasteful number, since it uses less digits than its factorization.

728051521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3695890.

The product of its (nonzero) digits is 5600, while the sum is 31.

The square root of 728051521 is about 26982.4298572238. The cubic root of 728051521 is about 899.6095100235.

The spelling of 728051521 in words is "seven hundred twenty-eight million, fifty-one thousand, five hundred twenty-one".