728139889 has 4 divisors (see below), whose sum is σ = 728917924. Its totient is φ = 727361856.

The previous prime is 728139877. The next prime is 728139899. The reversal of 728139889 is 988931827.

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 41280625 + 686859264 = 6425^2 + 26208^2 .

It is a cyclic number.

It is not a de Polignac number, because 728139889 - 2¹³ = 728131697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (728139829) 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, 387612 + ... + 389485.

It is an arithmetic number, because the mean of its divisors is an integer number (182229481).

Almost surely, 2^728139889 is an apocalyptic number.

It is an amenable number.

728139889 is a deficient number, since it is larger than the sum of its proper divisors (778035).

728139889 is an equidigital number, since it uses as much as digits as its factorization.

728139889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 778034.

The product of its digits is 1741824, while the sum is 55.

The square root of 728139889 is about 26984.0673175858. The cubic root of 728139889 is about 899.6459055599.

It can be divided in two parts, 728139 and 889, that added together give a triangular number (729028 = T₁₂₀₇).

The spelling of 728139889 in words is "seven hundred twenty-eight million, one hundred thirty-nine thousand, eight hundred eighty-nine".