28656840 has 64 divisors (see below), whose sum is σ = 87816960. Its totient is φ = 7477760.

The previous prime is 28656811. The next prime is 28656841. The reversal of 28656840 is 4865682.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (28656841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3100 + ... + 8180.

It is an arithmetic number, because the mean of its divisors is an integer number (1372140).

Almost surely, 2^28656840 is an apocalyptic number.

28656840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28656840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43908480).

28656840 is an abundant number, since it is smaller than the sum of its proper divisors (59160120).

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

28656840 is a wasteful number, since it uses less digits than its factorization.

28656840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5142 (or 5138 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 39.

The square root of 28656840 is about 5353.2083837639. The cubic root of 28656840 is about 306.0150362127.

The spelling of 28656840 in words is "twenty-eight million, six hundred fifty-six thousand, eight hundred forty".