28505857920 has 128 divisors (see below), whose sum is σ = 91407536640. Its totient is φ = 7555958784.

The previous prime is 28505857903. The next prime is 28505857931. The reversal of 28505857920 is 2975850582.

It is a tau number, because it is divible by the number of its divisors (128).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 276189 + ... + 365091.

It is an arithmetic number, because the mean of its divisors is an integer number (714121380).

Almost surely, 2^28505857920 is an apocalyptic number.

28505857920 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 28505857920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45703768320).

28505857920 is an abundant number, since it is smaller than the sum of its proper divisors (62901678720).

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

28505857920 is a wasteful number, since it uses less digits than its factorization.

28505857920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89092 (or 89080 counting only the distinct ones).

The product of its (nonzero) digits is 2016000, while the sum is 51.

The spelling of 28505857920 in words is "twenty-eight billion, five hundred five million, eight hundred fifty-seven thousand, nine hundred twenty".