28394440 has 16 divisors (see below), whose sum is σ = 63887580. Its totient is φ = 11357760.

The previous prime is 28394413. The next prime is 28394441. The reversal of 28394440 is 4449382.

It can be written as a sum of positive squares in 2 ways, for example, as 28323684 + 70756 = 5322^2 + 266^2 .

It is a junction number, because it is equal to n+sod(n) for n = 28394396 and 28394405.

It is not an unprimeable number, because it can be changed into a prime (28394441) by changing a digit.

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, 354891 + ... + 354970.

Almost surely, 2^28394440 is an apocalyptic number.

28394440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28394440 is an abundant number, since it is smaller than the sum of its proper divisors (35493140).

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

28394440 is a wasteful number, since it uses less digits than its factorization.

28394440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 709872 (or 709868 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 34.

The square root of 28394440 is about 5328.6433545509. The cubic root of 28394440 is about 305.0781489255.

The spelling of 28394440 in words is "twenty-eight million, three hundred ninety-four thousand, four hundred forty".