28545921 has 24 divisors (see below), whose sum is σ = 43280640. Its totient is φ = 18095616.

The previous prime is 28545919. The next prime is 28545929. The reversal of 28545921 is 12954582.

28545921 is a `hidden beast` number, since 28 + 545 + 92 + 1 = 666.

It is not a de Polignac number, because 28545921 - 2¹ = 28545919 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28545929) 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, 49185 + ... + 49761.

It is an arithmetic number, because the mean of its divisors is an integer number (1803360).

Almost surely, 2^28545921 is an apocalyptic number.

It is an amenable number.

28545921 is a deficient number, since it is larger than the sum of its proper divisors (14734719).

28545921 is a wasteful number, since it uses less digits than its factorization.

28545921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 845 (or 842 counting only the distinct ones).

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

The square root of 28545921 is about 5342.8382906466. The cubic root of 28545921 is about 305.6197057058.

The spelling of 28545921 in words is "twenty-eight million, five hundred forty-five thousand, nine hundred twenty-one".