28091556867 has 54 divisors (see below), whose sum is σ = 43544930436. Its totient is φ = 16094287440.

The previous prime is 28091556839. The next prime is 28091556893. The reversal of 28091556867 is 76865519082.

It is not a de Polignac number, because 28091556867 - 2²⁷ = 27957339139 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is not an unprimeable number, because it can be changed into a prime (28091554867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 60672678 + ... + 60673140.

Almost surely, 2^28091556867 is an apocalyptic number.

28091556867 is a deficient number, since it is larger than the sum of its proper divisors (15453373569).

28091556867 is an equidigital number, since it uses as much as digits as its factorization.

28091556867 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 989 (or 496 counting only the distinct ones).

The product of its (nonzero) digits is 7257600, while the sum is 57.

The spelling of 28091556867 in words is "twenty-eight billion, ninety-one million, five hundred fifty-six thousand, eight hundred sixty-seven".