28347227521 has 4 divisors (see below), whose sum is σ = 28360469844. Its totient is φ = 28333985200.

The previous prime is 28347227509. The next prime is 28347227527. The reversal of 28347227521 is 12572274382.

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 27635405121 + 711822400 = 166239^2 + 26680^2 .

It is a cyclic number.

It is not a de Polignac number, because 28347227521 - 2⁷ = 28347227393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28347227527) 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, 6617950 + ... + 6622231.

It is an arithmetic number, because the mean of its divisors is an integer number (7090117461).

Almost surely, 2^28347227521 is an apocalyptic number.

It is an amenable number.

28347227521 is a deficient number, since it is larger than the sum of its proper divisors (13242323).

28347227521 is a wasteful number, since it uses less digits than its factorization.

28347227521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13242322.

The product of its digits is 376320, while the sum is 43.

The spelling of 28347227521 in words is "twenty-eight billion, three hundred forty-seven million, two hundred twenty-seven thousand, five hundred twenty-one".