640799459209728 has 1600 divisors, whose sum is σ = 2479538666035200. Its totient is φ = 163548912844800.

The previous prime is 640799459209661. The next prime is 640799459209747. The reversal of 640799459209728 is 827902954997046.

640799459209728 is a `hidden beast` number, since 6 + 4 + 0 + 7 + 99 + 459 + 2 + 0 + 9 + 72 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (81).

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 5732577198 + ... + 5732688978.

It is an arithmetic number, because the mean of its divisors is an integer number (1549711666272).

Almost surely, 2^{640799459209728} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640799459209728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1239769333017600).

640799459209728 is an abundant number, since it is smaller than the sum of its proper divisors (1838739206825472).

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

640799459209728 is a wasteful number, since it uses less digits than its factorization.

640799459209728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111876 (or 111837 counting only the distinct ones).

The product of its (nonzero) digits is 4938071040, while the sum is 81.

The spelling of 640799459209728 in words is "six hundred forty trillion, seven hundred ninety-nine billion, four hundred fifty-nine million, two hundred nine thousand, seven hundred twenty-eight".