28206584640 has 784 divisors, whose sum is σ = 110817818496. Its totient is φ = 6793113600.

The previous prime is 28206584633. The next prime is 28206584641. The reversal of 28206584640 is 4648560282.

28206584640 is a `hidden beast` number, since 2 + 8 + 2 + 0 + 6 + 584 + 64 + 0 = 666.

It is a super-2 number, since 2×28206584640² (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 (28206584641) by changing a digit.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 215317375 + ... + 215317505.

Almost surely, 2^28206584640 is an apocalyptic number.

28206584640 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 28206584640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (55408909248).

28206584640 is an abundant number, since it is smaller than the sum of its proper divisors (82611233856).

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

28206584640 is a wasteful number, since it uses less digits than its factorization.

28206584640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 250 (or 225 counting only the distinct ones).

The product of its (nonzero) digits is 737280, while the sum is 45.

The spelling of 28206584640 in words is "twenty-eight billion, two hundred six million, five hundred eighty-four thousand, six hundred forty".