640728971910720 has 2240 divisors, whose sum is σ = 3112488258485760. Its totient is φ = 120985701580800.

The previous prime is 640728971910707. The next prime is 640728971910743. The reversal of 640728971910720 is 27019179827046.

640728971910720 is a `hidden beast` number, since 6 + 407 + 2 + 8 + 9 + 71 + 91 + 0 + 72 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (2240).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 319 ways as a sum of consecutive naturals, for example, 983623530 + ... + 984274710.

It is an arithmetic number, because the mean of its divisors is an integer number (1389503686824).

Almost surely, 2^{640728971910720} is an apocalyptic number.

640728971910720 is a gapful number since it is divisible by the number (60) 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 640728971910720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1556244129242880).

640728971910720 is an abundant number, since it is smaller than the sum of its proper divisors (2471759286575040).

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

640728971910720 is a wasteful number, since it uses less digits than its factorization.

640728971910720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 651274 (or 651255 counting only the distinct ones).

The product of its (nonzero) digits is 21337344, while the sum is 63.

The spelling of 640728971910720 in words is "six hundred forty trillion, seven hundred twenty-eight billion, nine hundred seventy-one million, nine hundred ten thousand, seven hundred twenty".