640985823744 has 160 divisors (see below), whose sum is σ = 1975088586240. Its totient is φ = 180932063232.

The previous prime is 640985823691. The next prime is 640985823749. The reversal of 640985823744 is 447328589046.

640985823744 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (640985823749) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 533287 + ... + 1251545.

It is an arithmetic number, because the mean of its divisors is an integer number (12344303664).

Almost surely, 2^640985823744 is an apocalyptic number.

640985823744 is a gapful number since it is divisible by the number (64) 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 640985823744, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (987544293120).

640985823744 is an abundant number, since it is smaller than the sum of its proper divisors (1334102762496).

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

640985823744 is an equidigital number, since it uses as much as digits as its factorization.

640985823744 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 718370 (or 718354 counting only the distinct ones).

The product of its (nonzero) digits is 46448640, while the sum is 60.

The spelling of 640985823744 in words is "six hundred forty billion, nine hundred eighty-five million, eight hundred twenty-three thousand, seven hundred forty-four".