28791387 has 12 divisors (see below), whose sum is σ = 44034120. Its totient is φ = 18065088.

The previous prime is 28791379. The next prime is 28791397. The reversal of 28791387 is 78319782.

It is not a de Polignac number, because 28791387 - 2³ = 28791379 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (28791317) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 93937 + ... + 94242.

It is an arithmetic number, because the mean of its divisors is an integer number (3669510).

Almost surely, 2^28791387 is an apocalyptic number.

28791387 is a deficient number, since it is larger than the sum of its proper divisors (15242733).

28791387 is a wasteful number, since it uses less digits than its factorization.

28791387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188202 (or 188199 counting only the distinct ones).

The product of its digits is 169344, while the sum is 45.

The square root of 28791387 is about 5365.7606170980. The cubic root of 28791387 is about 306.4932133222.

The spelling of 28791387 in words is "twenty-eight million, seven hundred ninety-one thousand, three hundred eighty-seven".