28328643 has 32 divisors (see below), whose sum is σ = 49272320. Its totient is φ = 15746400.

The previous prime is 28328633. The next prime is 28328683. The reversal of 28328643 is 34682382.

28328643 is a `hidden beast` number, since 2 + 8 + 3 + 2 + 8 + 643 = 666.

It is not a de Polignac number, because 28328643 - 2⁴ = 28328627 is a prime.

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

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28328598 and 28328607.

It is not an unprimeable number, because it can be changed into a prime (28328623) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4968 + ... + 9018.

It is an arithmetic number, because the mean of its divisors is an integer number (1539760).

Almost surely, 2^28328643 is an apocalyptic number.

28328643 is a deficient number, since it is larger than the sum of its proper divisors (20943677).

28328643 is a wasteful number, since it uses less digits than its factorization.

28328643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4104 (or 4098 counting only the distinct ones).

The product of its digits is 55296, while the sum is 36.

The square root of 28328643 is about 5322.4658758887. The cubic root of 28328643 is about 304.8423192837.

The spelling of 28328643 in words is "twenty-eight million, three hundred twenty-eight thousand, six hundred forty-three".