28399040 has 28 divisors (see below), whose sum is σ = 67625976. Its totient is φ = 11359488.

The previous prime is 28399037. The next prime is 28399073. The reversal of 28399040 is 4099382.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44054 + ... + 44693.

Almost surely, 2^28399040 is an apocalyptic number.

28399040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28399040 is an abundant number, since it is smaller than the sum of its proper divisors (39226936).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28399040 is an equidigital number, since it uses as much as digits as its factorization.

28399040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88764 (or 88754 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 28399040 is about 5329.0749666335. The cubic root of 28399040 is about 305.0946226167.

The spelling of 28399040 in words is "twenty-eight million, three hundred ninety-nine thousand, forty".