28001545209 has 30 divisors (see below), whose sum is σ = 45977861930. Its totient is φ = 16970627520.

The previous prime is 28001545193. The next prime is 28001545213. The reversal of 28001545209 is 90254510082.

28001545209 is a `hidden beast` number, since 2 + 80 + 0 + 1 + 54 + 520 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 26586280809 + 1415264400 = 163053^2 + 37620^2 .

It is not a de Polignac number, because 28001545209 - 2⁴ = 28001545193 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28001540209) by changing a digit.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 1418704 + ... + 1438305.

Almost surely, 2^28001545209 is an apocalyptic number.

It is an amenable number.

28001545209 is a deficient number, since it is larger than the sum of its proper divisors (17976316721).

28001545209 is a wasteful number, since it uses less digits than its factorization.

28001545209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2857043 (or 2857023 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 36.

The spelling of 28001545209 in words is "twenty-eight billion, one million, five hundred forty-five thousand, two hundred nine".