28557405 has 12 divisors (see below), whose sum is σ = 49499580. Its totient is φ = 15230592.

The previous prime is 28557391. The next prime is 28557427. The reversal of 28557405 is 50475582.

It is a happy number.

28557405 is a `hidden beast` number, since 2 + 85 + 574 + 0 + 5 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 13972644 + 14584761 = 3738^2 + 3819^2 .

It is not a de Polignac number, because 28557405 - 2⁸ = 28557149 is a prime.

It is a super-3 number, since 3×28557405³ (a number of 23 digits) contains 333 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 28557405.

It is a congruent number.

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 11 ways as a sum of consecutive naturals, for example, 317260 + ... + 317349.

It is an arithmetic number, because the mean of its divisors is an integer number (4124965).

Almost surely, 2^28557405 is an apocalyptic number.

It is an amenable number.

28557405 is a deficient number, since it is larger than the sum of its proper divisors (20942175).

28557405 is a wasteful number, since it uses less digits than its factorization.

28557405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 634620 (or 634617 counting only the distinct ones).

The product of its (nonzero) digits is 56000, while the sum is 36.

The square root of 28557405 is about 5343.9128922541. The cubic root of 28557405 is about 305.6606837279.

The spelling of 28557405 in words is "twenty-eight million, five hundred fifty-seven thousand, four hundred five".