28509511680 has 560 divisors, whose sum is σ = 110234129544. Its totient is φ = 7007109120.

The previous prime is 28509511673. The next prime is 28509511711. The reversal of 28509511680 is 8611590582.

It is a happy number.

28509511680 is a `hidden beast` number, since 2 + 8 + 50 + 9 + 511 + 6 + 80 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 21913473024 + 6596038656 = 148032^2 + 81216^2 .

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

It is a congruent number.

It is an unprimeable number.

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 39 ways as a sum of consecutive naturals, for example, 43130550 + ... + 43131210.

Almost surely, 2^28509511680 is an apocalyptic number.

28509511680 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 28509511680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (55117064772).

28509511680 is an abundant number, since it is smaller than the sum of its proper divisors (81724617864).

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

28509511680 is an equidigital number, since it uses as much as digits as its factorization.

28509511680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 717 (or 684 counting only the distinct ones).

The product of its (nonzero) digits is 172800, while the sum is 45.

The spelling of 28509511680 in words is "twenty-eight billion, five hundred nine million, five hundred eleven thousand, six hundred eighty".