28203440 has 20 divisors (see below), whose sum is σ = 65573184. Its totient is φ = 11281344.

The previous prime is 28203433. The next prime is 28203481. The reversal of 28203440 is 4430282.

It is a tau number, because it is divible by the number of its divisors (20).

It is an unprimeable number.

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, 176192 + ... + 176351.

Almost surely, 2^28203440 is an apocalyptic number.

28203440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28203440 is an abundant number, since it is smaller than the sum of its proper divisors (37369744).

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

28203440 is a wasteful number, since it uses less digits than its factorization.

28203440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 352556 (or 352550 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 23.

The square root of 28203440 is about 5310.6911038018. The cubic root of 28203440 is about 304.3925561231.

The spelling of 28203440 in words is "twenty-eight million, two hundred three thousand, four hundred forty".