28315840521 has 4 divisors (see below), whose sum is σ = 37754454032. Its totient is φ = 18877227012.

The previous prime is 28315840513. The next prime is 28315840561. The reversal of 28315840521 is 12504851382.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 28315840521 - 2³ = 28315840513 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28315840521.

It is not an unprimeable number, because it can be changed into a prime (28315840561) 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, 4719306751 + ... + 4719306756.

It is an arithmetic number, because the mean of its divisors is an integer number (9438613508).

Almost surely, 2^28315840521 is an apocalyptic number.

It is an amenable number.

28315840521 is a deficient number, since it is larger than the sum of its proper divisors (9438613511).

28315840521 is an equidigital number, since it uses as much as digits as its factorization.

28315840521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9438613510.

The product of its (nonzero) digits is 76800, while the sum is 39.

The spelling of 28315840521 in words is "twenty-eight billion, three hundred fifteen million, eight hundred forty thousand, five hundred twenty-one".