28509085521 has 12 divisors (see below), whose sum is σ = 47062617472. Its totient is φ = 16290905976.

The previous prime is 28509085499. The next prime is 28509085523. The reversal of 28509085521 is 12558090582.

It is a happy number.

28509085521 is a `hidden beast` number, since 2 + 8 + 5 + 0 + 90 + 8 + 552 + 1 = 666.

It is not a de Polignac number, because 28509085521 - 2¹³ = 28509077329 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28509085523) 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 11 ways as a sum of consecutive naturals, for example, 226262521 + ... + 226262646.

Almost surely, 2^28509085521 is an apocalyptic number.

28509085521 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

28509085521 is a deficient number, since it is larger than the sum of its proper divisors (18553531951).

28509085521 is a wasteful number, since it uses less digits than its factorization.

28509085521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 452525180 (or 452525177 counting only the distinct ones).

The product of its (nonzero) digits is 288000, while the sum is 45.

The spelling of 28509085521 in words is "twenty-eight billion, five hundred nine million, eighty-five thousand, five hundred twenty-one".