28788389 has 4 divisors (see below), whose sum is σ = 32901024. Its totient is φ = 24675756.

The previous prime is 28788377. The next prime is 28788407. The reversal of 28788389 is 98388782.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 28788389 - 2⁴ = 28788373 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28788389.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28788349) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2056307 + ... + 2056320.

It is an arithmetic number, because the mean of its divisors is an integer number (8225256).

Almost surely, 2^28788389 is an apocalyptic number.

It is an amenable number.

28788389 is a deficient number, since it is larger than the sum of its proper divisors (4112635).

28788389 is an equidigital number, since it uses as much as digits as its factorization.

28788389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4112634.

The product of its digits is 1548288, while the sum is 53.

The square root of 28788389 is about 5365.4812458903. The cubic root of 28788389 is about 306.4825747407.

The spelling of 28788389 in words is "twenty-eight million, seven hundred eighty-eight thousand, three hundred eighty-nine".