13728398221 has 8 divisors (see below), whose sum is σ = 14136111864. Its totient is φ = 13324154880.

The previous prime is 13728398197. The next prime is 13728398227. The reversal of 13728398221 is 12289382731.

It can be written as a sum of positive squares in 4 ways, for example, as 12709225 + 13715688996 = 3565^2 + 117114^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 13728398221 - 2¹⁷ = 13728267149 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13728398227) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 859546 + ... + 875371.

It is an arithmetic number, because the mean of its divisors is an integer number (1767013983).

Almost surely, 2^13728398221 is an apocalyptic number.

It is an amenable number.

13728398221 is a deficient number, since it is larger than the sum of its proper divisors (407713643).

13728398221 is a wasteful number, since it uses less digits than its factorization.

13728398221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1735151.

The product of its digits is 290304, while the sum is 46.

The spelling of 13728398221 in words is "thirteen billion, seven hundred twenty-eight million, three hundred ninety-eight thousand, two hundred twenty-one".