28656566840 has 64 divisors (see below), whose sum is σ = 74040912000. Its totient is φ = 9872115840.

The previous prime is 28656566837. The next prime is 28656566849. The reversal of 28656566840 is 4866565682.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28656566849) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1705550 + ... + 1722269.

It is an arithmetic number, because the mean of its divisors is an integer number (1156889250).

Almost surely, 2^28656566840 is an apocalyptic number.

28656566840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28656566840 is an abundant number, since it is smaller than the sum of its proper divisors (45384345160).

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

28656566840 is a wasteful number, since it uses less digits than its factorization.

28656566840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3427860 (or 3427856 counting only the distinct ones).

The product of its (nonzero) digits is 16588800, while the sum is 56.

The spelling of 28656566840 in words is "twenty-eight billion, six hundred fifty-six million, five hundred sixty-six thousand, eight hundred forty".