28788665 has 4 divisors (see below), whose sum is σ = 34546404. Its totient is φ = 23030928.

The previous prime is 28788659. The next prime is 28788673. The reversal of 28788665 is 56688782.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56688782 = 2 ⋅28344391.

It can be written as a sum of positive squares in 2 ways, for example, as 11215801 + 17572864 = 3349^2 + 4192^2 .

It is a cyclic number.

It is not a de Polignac number, because 28788665 - 2¹⁶ = 28723129 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2878862 + ... + 2878871.

It is an arithmetic number, because the mean of its divisors is an integer number (8636601).

Almost surely, 2^28788665 is an apocalyptic number.

It is an amenable number.

28788665 is a deficient number, since it is larger than the sum of its proper divisors (5757739).

28788665 is an equidigital number, since it uses as much as digits as its factorization.

28788665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5757738.

The product of its digits is 1290240, while the sum is 50.

The square root of 28788665 is about 5365.5069657955. The cubic root of 28788665 is about 306.4835541740.

The spelling of 28788665 in words is "twenty-eight million, seven hundred eighty-eight thousand, six hundred sixty-five".