28318208021 has 4 divisors (see below), whose sum is σ = 28418984844. Its totient is φ = 28217431200.

The previous prime is 28318207933. The next prime is 28318208027. The reversal of 28318208021 is 12080281382.

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 12636907396 + 15681300625 = 112414^2 + 125225^2 .

It is a cyclic number.

It is not a de Polignac number, because 28318208021 - 2¹⁰ = 28318206997 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 (28318208027) 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, 50387990 + ... + 50388551.

It is an arithmetic number, because the mean of its divisors is an integer number (7104746211).

Almost surely, 2^28318208021 is an apocalyptic number.

It is an amenable number.

28318208021 is a deficient number, since it is larger than the sum of its proper divisors (100776823).

28318208021 is a wasteful number, since it uses less digits than its factorization.

28318208021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100776822.

The product of its (nonzero) digits is 12288, while the sum is 35.

The spelling of 28318208021 in words is "twenty-eight billion, three hundred eighteen million, two hundred eight thousand, twenty-one".