28398869 has 4 divisors (see below), whose sum is σ = 29166444. Its totient is φ = 27631296.

The previous prime is 28398847. The next prime is 28398889. The reversal of 28398869 is 96889382.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18601969 + 9796900 = 4313^2 + 3130^2 .

It is a cyclic number.

It is not a de Polignac number, because 28398869 - 2⁸ = 28398613 is a prime.

It is a super-2 number, since 2×28398869² = 1612991520958322, which contains 22 as substring.

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 28398869.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28398809) 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, 383732 + ... + 383805.

It is an arithmetic number, because the mean of its divisors is an integer number (7291611).

Almost surely, 2^28398869 is an apocalyptic number.

It is an amenable number.

28398869 is a deficient number, since it is larger than the sum of its proper divisors (767575).

28398869 is an equidigital number, since it uses as much as digits as its factorization.

28398869 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 767574.

The product of its digits is 1492992, while the sum is 53.

The square root of 28398869 is about 5329.0589225491. The cubic root of 28398869 is about 305.0940102570.

The spelling of 28398869 in words is "twenty-eight million, three hundred ninety-eight thousand, eight hundred sixty-nine".