28256811840 has 84 divisors (see below), whose sum is σ = 97191668964. Its totient is φ = 7535149056.

The previous prime is 28256811839. The next prime is 28256811841. The reversal of 28256811840 is 4811865282.

28256811840 is a `hidden beast` number, since 2 + 8 + 2 + 568 + 1 + 1 + 84 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (28256811839) and next prime (28256811841).

It can be written as a sum of positive squares in 2 ways, for example, as 14730191424 + 13526620416 = 121368^2 + 116304^2 .

It is a super-2 number, since 2×28256811840² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28256811841) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4902817 + ... + 4908576.

Almost surely, 2^28256811840 is an apocalyptic number.

28256811840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28256811840 is an abundant number, since it is smaller than the sum of its proper divisors (68934857124).

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

28256811840 is a wasteful number, since it uses less digits than its factorization.

28256811840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9811416 (or 9811403 counting only the distinct ones).

The product of its (nonzero) digits is 245760, while the sum is 45.

The spelling of 28256811840 in words is "twenty-eight billion, two hundred fifty-six million, eight hundred eleven thousand, eight hundred forty".