28089731 has 4 divisors (see below), whose sum is σ = 28189272. Its totient is φ = 27990192.

The previous prime is 28089713. The next prime is 28089767. The reversal of 28089731 is 13798082.

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

It is a cyclic number.

It is not a de Polignac number, because 28089731 - 2⁶ = 28089667 is a prime.

It is a super-2 number, since 2×28089731² = 1578065975304722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28089701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 49346 + ... + 49911.

It is an arithmetic number, because the mean of its divisors is an integer number (7047318).

Almost surely, 2^28089731 is an apocalyptic number.

28089731 is a deficient number, since it is larger than the sum of its proper divisors (99541).

28089731 is an equidigital number, since it uses as much as digits as its factorization.

28089731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99540.

The product of its (nonzero) digits is 24192, while the sum is 38.

The square root of 28089731 is about 5299.9746225808. The cubic root of 28089731 is about 303.9829276828.

The spelling of 28089731 in words is "twenty-eight million, eighty-nine thousand, seven hundred thirty-one".