728955656521 has 27 divisors (see below), whose sum is σ = 769513728711. Its totient is φ = 690503561328.

The previous prime is 728955656519. The next prime is 728955656563. The reversal of 728955656521 is 125656559827.

The square root of 728955656521 is 853789.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 382246664121 + 346708992400 = 618261^2 + 588820^2 .

It is not a de Polignac number, because 728955656521 - 2¹ = 728955656519 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 728955656521.

It is not an unprimeable number, because it can be changed into a prime (728952656521) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 1460832730 + ... + 1460833228.

Almost surely, 2^728955656521 is an apocalyptic number.

728955656521 is the 853789-th square number.

728955656521 is the 426895-th centered octagonal number.

It is an amenable number.

728955656521 is a deficient number, since it is larger than the sum of its proper divisors (40558072190).

728955656521 is an frugal number, since it uses more digits than its factorization.

728955656521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1174 (or 587 counting only the distinct ones).

The product of its digits is 45360000, while the sum is 61.

The spelling of 728955656521 in words is "seven hundred twenty-eight billion, nine hundred fifty-five million, six hundred fifty-six thousand, five hundred twenty-one".