28688369 has 4 divisors (see below), whose sum is σ = 29034096. Its totient is φ = 28342644.

The previous prime is 28688323. The next prime is 28688371. The reversal of 28688369 is 96388682.

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 a cyclic number.

It is not a de Polignac number, because 28688369 - 2²⁰ = 27639793 is a prime.

It is a super-2 number, since 2×28688369² = 1646045031760322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28688389) 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, 172739 + ... + 172904.

It is an arithmetic number, because the mean of its divisors is an integer number (7258524).

Almost surely, 2^28688369 is an apocalyptic number.

It is an amenable number.

28688369 is a deficient number, since it is larger than the sum of its proper divisors (345727).

28688369 is an equidigital number, since it uses as much as digits as its factorization.

28688369 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 345726.

The product of its digits is 995328, while the sum is 50.

The square root of 28688369 is about 5356.1524436857. The cubic root of 28688369 is about 306.1272236438.

The spelling of 28688369 in words is "twenty-eight million, six hundred eighty-eight thousand, three hundred sixty-nine".