28789891 has 24 divisors (see below), whose sum is σ = 33696320. Its totient is φ = 24440832.

The previous prime is 28789889. The next prime is 28789903. The reversal of 28789891 is 19898782.

It is not a de Polignac number, because 28789891 - 2¹ = 28789889 is a prime.

It is a Smith number, since the sum of its digits (52) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28789841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 296755 + ... + 296851.

Almost surely, 2^28789891 is an apocalyptic number.

28789891 is a deficient number, since it is larger than the sum of its proper divisors (4906429).

28789891 is a wasteful number, since it uses less digits than its factorization.

28789891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223 (or 206 counting only the distinct ones).

The product of its digits is 580608, while the sum is 52.

The square root of 28789891 is about 5365.6212128700. The cubic root of 28789891 is about 306.4879047695.

It can be divided in two parts, 2878 and 9891, that added together give a square (12769 = 113²).

The spelling of 28789891 in words is "twenty-eight million, seven hundred eighty-nine thousand, eight hundred ninety-one".