28639307840 has 336 divisors, whose sum is σ = 83212448256. Its totient is φ = 9297100800.

The previous prime is 28639307797. The next prime is 28639307861. The reversal of 28639307840 is 4870393682.

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, 18440504 + ... + 18442056.

It is an arithmetic number, because the mean of its divisors is an integer number (247656096).

Almost surely, 2^28639307840 is an apocalyptic number.

28639307840 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 28639307840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41606224128).

28639307840 is an abundant number, since it is smaller than the sum of its proper divisors (54573140416).

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

28639307840 is a wasteful number, since it uses less digits than its factorization.

28639307840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1638 (or 1615 counting only the distinct ones).

The product of its (nonzero) digits is 1741824, while the sum is 50.

The spelling of 28639307840 in words is "twenty-eight billion, six hundred thirty-nine million, three hundred seven thousand, eight hundred forty".