28557540 has 72 divisors (see below), whose sum is σ = 94506048. Its totient is φ = 6922560.

The previous prime is 28557539. The next prime is 28557553. The reversal of 28557540 is 4575582.

It is a happy number.

28557540 is a `hidden beast` number, since 2 + 85 + 575 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 28557495 and 28557504.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5232 + ... + 9191.

It is an arithmetic number, because the mean of its divisors is an integer number (1312584).

Almost surely, 2^28557540 is an apocalyptic number.

28557540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28557540 is an abundant number, since it is smaller than the sum of its proper divisors (65948508).

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

28557540 is a wasteful number, since it uses less digits than its factorization.

28557540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14449 (or 14444 counting only the distinct ones).

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

The square root of 28557540 is about 5343.9255234331. The cubic root of 28557540 is about 305.6611653792.

The spelling of 28557540 in words is "twenty-eight million, five hundred fifty-seven thousand, five hundred forty".