28547855991 has 24 divisors (see below), whose sum is σ = 41488115760. Its totient is φ = 18915561600.

The previous prime is 28547855957. The next prime is 28547856017. The reversal of 28547855991 is 19955874582.

28547855991 is a `hidden beast` number, since 2 + 8 + 5 + 4 + 78 + 559 + 9 + 1 = 666.

It is not a de Polignac number, because 28547855991 - 2²⁵ = 28514301559 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28547855951) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4219051 + ... + 4225811.

It is an arithmetic number, because the mean of its divisors is an integer number (1728671490).

Almost surely, 2^28547855991 is an apocalyptic number.

28547855991 is a deficient number, since it is larger than the sum of its proper divisors (12940259769).

28547855991 is a wasteful number, since it uses less digits than its factorization.

28547855991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9567 (or 9564 counting only the distinct ones).

The product of its digits is 36288000, while the sum is 63.

The spelling of 28547855991 in words is "twenty-eight billion, five hundred forty-seven million, eight hundred fifty-five thousand, nine hundred ninety-one".