640741918320 has 640 divisors, whose sum is σ = 2579834880000. Its totient is φ = 146110003200.

The previous prime is 640741918301. The next prime is 640741918337. The reversal of 640741918320 is 23819147046.

640741918320 is a `hidden beast` number, since 6 + 407 + 41 + 9 + 183 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 445268161 + ... + 445269599.

It is an arithmetic number, because the mean of its divisors is an integer number (4030992000).

Almost surely, 2^640741918320 is an apocalyptic number.

640741918320 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 640741918320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1289917440000).

640741918320 is an abundant number, since it is smaller than the sum of its proper divisors (1939092961680).

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

640741918320 is a wasteful number, since it uses less digits than its factorization.

640741918320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2083 (or 2057 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 45.

The spelling of 640741918320 in words is "six hundred forty billion, seven hundred forty-one million, nine hundred eighteen thousand, three hundred twenty".