28991654640 has 240 divisors, whose sum is σ = 110372414880. Its totient is φ = 6760765440.

The previous prime is 28991654591. The next prime is 28991654683. The reversal of 28991654640 is 4645619982.

28991654640 is a `hidden beast` number, since 2 + 8 + 9 + 91 + 6 + 546 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 96330 + ... + 259350.

It is an arithmetic number, because the mean of its divisors is an integer number (459885062).

Almost surely, 2^28991654640 is an apocalyptic number.

28991654640 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 28991654640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (55186207440).

28991654640 is an abundant number, since it is smaller than the sum of its proper divisors (81380760240).

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

28991654640 is a wasteful number, since it uses less digits than its factorization.

28991654640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163072 (or 163063 counting only the distinct ones).

The product of its (nonzero) digits is 3732480, while the sum is 54.

The spelling of 28991654640 in words is "twenty-eight billion, nine hundred ninety-one million, six hundred fifty-four thousand, six hundred forty".