13320640728 has 128 divisors (see below), whose sum is σ = 38271744000. Its totient is φ = 4288394880.

The previous prime is 13320640709. The next prime is 13320640741. The reversal of 13320640728 is 82704602331.

It is a happy number.

13320640728 is a `hidden beast` number, since 1 + 3 + 3 + 2 + 0 + 640 + 7 + 2 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 13320640692 and 13320640701.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3928858 + ... + 3932246.

It is an arithmetic number, because the mean of its divisors is an integer number (298998000).

Almost surely, 2^13320640728 is an apocalyptic number.

13320640728 is a gapful number since it is divisible by the number (18) 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 13320640728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (19135872000).

13320640728 is an abundant number, since it is smaller than the sum of its proper divisors (24951103272).

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

13320640728 is a wasteful number, since it uses less digits than its factorization.

13320640728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4022 (or 4012 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 36.

The spelling of 13320640728 in words is "thirteen billion, three hundred twenty million, six hundred forty thousand, seven hundred twenty-eight".