28404225 has 18 divisors (see below), whose sum is σ = 50875526. Its totient is φ = 15148800.

The previous prime is 28404203. The next prime is 28404239. The reversal of 28404225 is 52240482.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 16641 + 28387584 = 129^2 + 5328^2 .

It is not a de Polignac number, because 28404225 - 2¹¹ = 28402177 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 62896 + ... + 63345.

Almost surely, 2^28404225 is an apocalyptic number.

28404225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

28404225 is a deficient number, since it is larger than the sum of its proper divisors (22471301).

28404225 is a wasteful number, since it uses less digits than its factorization.

28404225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126257 (or 126249 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 27.

The square root of 28404225 is about 5329.5614266091. The cubic root of 28404225 is about 305.1131891992.

The spelling of 28404225 in words is "twenty-eight million, four hundred four thousand, two hundred twenty-five".