28390005 has 24 divisors (see below), whose sum is σ = 56239872. Its totient is φ = 12978144.

The previous prime is 28390003. The next prime is 28390091. The reversal of 28390005 is 50009382.

It is not a de Polignac number, because 28390005 - 2¹ = 28390003 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28390001) 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 23 ways as a sum of consecutive naturals, for example, 44749 + ... + 45378.

It is an arithmetic number, because the mean of its divisors is an integer number (2343328).

Almost surely, 2^28390005 is an apocalyptic number.

It is an amenable number.

28390005 is a deficient number, since it is larger than the sum of its proper divisors (27849867).

28390005 is a wasteful number, since it uses less digits than its factorization.

28390005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90145 (or 90142 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 28390005 is about 5328.2271911021. The cubic root of 28390005 is about 305.0622644537.

Adding to 28390005 its reverse (50009382), we get a palindrome (78399387).

The spelling of 28390005 in words is "twenty-eight million, three hundred ninety thousand, five".