728221582881 has 27 divisors (see below), whose sum is σ = 1139065302297. Its totient is φ = 448115878080.

The previous prime is 728221582799. The next prime is 728221582897. The reversal of 728221582881 is 188285122827.

The square root of 728221582881 is 853359.

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

728221582881 is a `hidden beast` number, since 72 + 82 + 215 + 8 + 288 + 1 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 572420862225 + 155800720656 = 756585^2 + 394716^2 .

It is not a de Polignac number, because 728221582881 - 2¹¹ = 728221580833 is a prime.

It is a super-2 number, since 2×728221582881² (a number of 25 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (728221582381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 33270061 + ... + 33291941.

Almost surely, 2^728221582881 is an apocalyptic number.

728221582881 is the 853359-th square number.

728221582881 is the 426680-th centered octagonal number.

It is an amenable number.

728221582881 is a deficient number, since it is larger than the sum of its proper divisors (410843719416).

728221582881 is an frugal number, since it uses more digits than its factorization.

728221582881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43794 (or 21897 counting only the distinct ones).

The product of its digits is 2293760, while the sum is 54.

The spelling of 728221582881 in words is "seven hundred twenty-eight billion, two hundred twenty-one million, five hundred eighty-two thousand, eight hundred eighty-one".