28991305728 has 576 divisors, whose sum is σ = 108055584000. Its totient is φ = 7518044160.

The previous prime is 28991305669. The next prime is 28991305747. The reversal of 28991305728 is 82750319982.

It is a tau number, because it is divible by the number of its divisors (576).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 46835403 + ... + 46836021.

It is an arithmetic number, because the mean of its divisors is an integer number (187596500).

Almost surely, 2^28991305728 is an apocalyptic number.

28991305728 is a gapful number since it is divisible by the number (28) 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 28991305728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (54027792000).

28991305728 is an abundant number, since it is smaller than the sum of its proper divisors (79064278272).

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

28991305728 is a wasteful number, since it uses less digits than its factorization.

28991305728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 679 (or 642 counting only the distinct ones).

The product of its (nonzero) digits is 2177280, while the sum is 54.

The spelling of 28991305728 in words is "twenty-eight billion, nine hundred ninety-one million, three hundred five thousand, seven hundred twenty-eight".