728738810881 has 4 divisors (see below), whose sum is σ = 728740536532. Its totient is φ = 728737085232.

The previous prime is 728738810879. The next prime is 728738810897. The reversal of 728738810881 is 188018837827.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 78593319025 + 650145491856 = 280345^2 + 806316^2 .

It is a cyclic number.

It is not a de Polignac number, because 728738810881 - 2¹ = 728738810879 is a prime.

It is a super-2 number, since 2×728738810881² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (728738817881) 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, 243295 + ... + 1231531.

It is an arithmetic number, because the mean of its divisors is an integer number (182185134133).

Almost surely, 2^728738810881 is an apocalyptic number.

It is an amenable number.

728738810881 is a deficient number, since it is larger than the sum of its proper divisors (1725651).

728738810881 is an equidigital number, since it uses as much as digits as its factorization.

728738810881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1725650.

The product of its (nonzero) digits is 9633792, while the sum is 61.

The spelling of 728738810881 in words is "seven hundred twenty-eight billion, seven hundred thirty-eight million, eight hundred ten thousand, eight hundred eighty-one".