28438163521 has 4 divisors (see below), whose sum is σ = 28463807700. Its totient is φ = 28412519344.

The previous prime is 28438163513. The next prime is 28438163573. The reversal of 28438163521 is 12536183482.

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 1257695296 + 27180468225 = 35464^2 + 164865^2 .

It is a cyclic number.

It is not a de Polignac number, because 28438163521 - 2³ = 28438163513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28438163921) 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 3 ways as a sum of consecutive naturals, for example, 12820426 + ... + 12822643.

It is an arithmetic number, because the mean of its divisors is an integer number (7115951925).

Almost surely, 2^28438163521 is an apocalyptic number.

It is an amenable number.

28438163521 is a deficient number, since it is larger than the sum of its proper divisors (25644179).

28438163521 is a wasteful number, since it uses less digits than its factorization.

28438163521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25644178.

The product of its digits is 276480, while the sum is 43.

The spelling of 28438163521 in words is "twenty-eight billion, four hundred thirty-eight million, one hundred sixty-three thousand, five hundred twenty-one".