28556840 has 32 divisors (see below), whose sum is σ = 69196680. Its totient is φ = 10543872.

The previous prime is 28556831. The next prime is 28556873. The reversal of 28556840 is 4865582.

It can be written as a sum of positive squares in 4 ways, for example, as 15697444 + 12859396 = 3962^2 + 3586^2 .

It is a super-2 number, since 2×28556840² = 1630986221571200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 28556794 and 28556803.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26939 + ... + 27978.

Almost surely, 2^28556840 is an apocalyptic number.

28556840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28556840 is an abundant number, since it is smaller than the sum of its proper divisors (40639840).

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

28556840 is a wasteful number, since it uses less digits than its factorization.

28556840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54941 (or 54937 counting only the distinct ones).

The product of its (nonzero) digits is 76800, while the sum is 38.

The square root of 28556840 is about 5343.8600281070. The cubic root of 28556840 is about 305.6586679119.

The spelling of 28556840 in words is "twenty-eight million, five hundred fifty-six thousand, eight hundred forty".